Abstract:
A turbine-pump system adapted for use with well liquid that is displaceable within a well conduit. The turbine-pump system may include a bowl assembly; and a bowl support device fixedly attachable to the bowl assembly and selectively engageable with the well conduit for holding a portion of the bowl assembly in substantially axially, radially and rotationally fixed relationship with the well conduit.

Description:
This application claims priority of U.S. Provisional Patent Application No. 61/888,484, filed Oct. 8, 2013, which is hereby incorporated by reference for all that it discloses. 
     This application also hereby incorporates by reference for all that it discloses, a related application Ser. No. 14/497,106 filed Sep. 25, 2014, entitled TURBINE PUMP SYSTEM BOWL ASSEMBLY having the same inventor and filing date as the present application. 
    
    
     BACKGROUND 
     There are many known pumping systems for raising well water or other liquids to the surface. However, raising liquids from deep wells presents problems that have not been adequately addressed by existing pump technology. Currently available electrical turbine pumps and electric submersible pumps have severe horsepower and pumping head and temperature limitations. 
     There are many applications for deep well pumping systems today. One such application is mine dewatering. Mine Dewatering depths range from 1,000 to 7,000 feet below ground surface. Capital costs for conventional deep well mine pumps are typically on the order of 1-10 million dollars per mine. 
     Another deep well pumping application is for water supplies. Water supplies include domestic drinking water for cities and large-scale irrigation projects. Water supply aquifer depths can be 3,000 ft. or deeper. Pumping hot water from geothermal deposits for energy production is another application for deep well pumps. Oil and gas wells used in tight shale reserves require large volumes of ground water that must often be pumped from deep wells. Petroleum pumping, including off shore petroleum pumping is another application for deep well pumps. 
     Some large scale, renewable energy storage systems are based on pumped water storage using vertical turbine-pumps. Vertical turbine-pumps are driven by an electric motor during pumping operations. Such turbine-pumps can also be operated in a reverse direction with injected water causing rotation of a drive shaft that causes rotation of a motor armature in an opposite direction such that the motor functions as an electrical generator. Renewable energy storage systems have a deep aquifer, which functions as a lower reservoir, and a shallower aquifer or a surface level reservoir, which functions as an upper reservoir. During periods of excess wind energy production, water is pumped from the lower reservoir to the upper reservoir. During periods of low wind production, water is released from the upper reservoir and injected into the lower reservoir. During this water injection the vertical turbine-pump functions as a power generator turbine. 
     The above are just a few of the many applications for deep well pump systems and vertical turbine-pump systems. However currently, deep well pump systems are extremely expensive to make and install, difficult and expensive to maintain, inefficient and unreliable. Thus, there is a great need today for reliable, efficient, relatively low maintenance and reasonably priced deep well turbine-pump systems. 
     SUMMARY 
     This specification discloses example embodiments of a well liquid turbine-pump system. The turbine-pump system may include a hollow driveshaft that is adapted to be rotatably positioned inside a well casing. In some embodiments, the turbine-pump system has a surface mounted driver that is adapted to rotate the hollow driveshaft. Some embodiments of the system include impeller members adapted to rotate with the hollow driveshaft. The impeller members may be positioned within associated diffuser members that are adapted to form a well liquid channeling enclosure around the impeller members. In some embodiments several impeller members are connected together in a continuous impeller subassembly that is positioned within a continuous diffuser subassembly. 
     Some embodiments of the turbine-pump system include at least one inflatable packer assembly that is sealingly engageable with a diffuser subassembly and the well casing. The inflatable packer member is adapted to hold the diffuser subassembly in relatively axially and radially fixed relationship with the well casing. In some embodiments a bowl assembly, comprising a series of continuously connected diffuser members, is supported by a single inflatable packer assembly. The seal between the bowl assembly and the well casing that is formed by the packer assembly, prevents well liquid from flowing around the bowl assembly instead of through the bowl assembly. 
     In some embodiments of the turbine-pump system, the hollow driveshaft has a working fluid passage extending axially through it. Bearings supporting the hollow drive shaft may be lubricated with working fluid transmitted through the hollow driveshaft. Inflatable packer assemblies supporting the bowl assemblies may be inflated with working fluid transmitted through the hollow driveshaft. 
     Some embodiments of the liquid turbine-pump system may provide one or more of the below described advantages. 
     Inflatable packer assemblies may be used that counteract the torque of the driveshaft and the weight of the drive shaft and other components. Such packer assemblies (sometimes referred to herein simply as “packers”) may support separate, axially spaced sections of the turbine-pump system, which may be modular components of the turbine-pump system. 
     The use of a hollow driveshaft facilitates packer inflation and bearing lubrication with working fluid pumped through the hollow driveshaft. The hollow driveshaft can withstand more torque than a solid driveshaft of the same weight, enabling use of larger, higher torque, surface mounted drive motors that may be operated at lower speeds than traditional pump motors for the same throughput. The use of larger drive motors allows much greater pumping rates than traditional deep well pumps. Also, threaded connection portions of each of the impeller members are provided with a relatively larger cross-sectional area than traditional impeller members because the diameter of the hollow driveshaft is proportionally larger than that of a conventional solid driveshaft of the same weight. The larger cross-sectional area of applicant&#39;s impeller members can withstand higher torque and vertical loading than the smaller impeller cross-sectional area associated with the use of a solid drive shaft. 
     The hollow driveshaft in some embodiments may be constructed from lengths of oil field drill pipe. Such oil field drill pipes are relatively easy to connect and disconnect compared to connecting and disconnecting large diameter pump columns used for conventional vertical centrifugal pump systems. 
     In the new turbine-pump system described herein, there is no well column positioned inside a well casing as there is in the prior art. The well column (column pipe) is eliminated. and the well casing itself is the primary conduit for transmitting well liquid. Thus, one heavy and expensive component of a turbine-pump system is eliminated in applicant&#39;s new turbine-pump system. The relatively larger internal diameter of a well casing provides for more efficient liquid flow within the well, since larger diameter conduits have inherently lower energy loss due to friction than smaller diameter conduits. 
     Applicant&#39;s use of inflatable packers and a hollow driveshaft in some embodiments facilitates the modular construction of bowl assemblies. Such modular construction may provide a number of advantages. The bowl assembly modules may all have identical construction, which may reduce manufacturing costs and help to standardize installation procedures. The modules are each individually supported by an associated packer, reducing the load that any single packer must support. Each packer supported bowl assembly module supports an associated length of hollow driveshaft and an impeller subassembly. Because the total weight of all the down-hole components of the system are distributed over separately supported modular units, the total length of the line shaft is essentially unlimited by weight considerations, enabling the system to pump from well depths of 10,000 ft. or more. 
     Modular construction makes it relatively easy to add length to the turbine-pump system, as required by falling liquid surface levels in the associated well. 
     The connection or disconnection of down-hole sections of applicant&#39;s turbine-pump system involves connecting and/or disconnecting sections of a hollow driveshaft. It does not require connection of heavy and unwieldy sections of a conventional pump column. The hollow driveshaft in some embodiments is constructed from lengths of oil field drill pipe, which are relatively easy to connect and disconnect compared to connecting and/or disconnecting large diameter pump columns and associated shafting for vertical turbine pumps or electric power cable for electric submersible pumps. 
     The use of a continuous impeller subassembly and a continuous diffuser subassembly in each bowl assembly enables the entire series of bowl assemblies to be rotated by a single surface driver. It also enables the use of a semi-open impeller blade and diffuser vane design with associated improved efficiency in parts fabrication and more efficient pump operation. Internal bypass or leakage within the bowl assembly is eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional elevation view of a prior art vertical pump system. 
         FIGS. 2A and 2B  are schematic, partially cross-sectional isometric views of upper and lower portions of an example embodiment a centrifugal turbine-pump system. 
         FIGS. 3A and 3B  are schematic cross-sectional views of a portion of an example embodiment of a bowl assembly for a centrifugal turbine-pump system. 
         FIG. 4  is a schematic cross-sectional view of a portion of an example embodiment of another bowl assembly. 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the term “turbine-pump” refers to turbines and to pumps and to apparatus, such as the electric submersible vertical turbine-pumps described in the Background, that may function in both turbine and pump operating modes. Thus, an apparatus referred to as a “turbine-pump” may be an apparatus that functions only as a turbine or an apparatus that functions only as a pump or an apparatus that functions as both a turbine and a pump. 
     As illustrated by  FIG. 1 , a well from which water is to be pumped by a conventional vertical turbine-pump assembly  510  comprises a cylindrical vertical well enclosure  550 . The vertical well enclosure  550 , is defined by an inner wall surface  554  of a tubular well casing  552 . The well casing  552  may be conventionally assembled in an excavated vertical well hole/shaft. The vertical turbine-pump assembly  510  includes a tubular well column (sometimes referred to in the art as a “column pipe”)  512  that is positioned in the vertical enclosure  550 , i.e., inside the tubular well casing  552 . An electric pump motor/generator  514  is mounted at a position  516  above the well column  512 . The well column  512  is in fluid communication with a bowl assembly  530  attached to the lower end  518  of the well column  512 . The well column  512  is typically made of a high strength metal such as cast iron or steel. 
     The bowl assembly  530  usually includes one or two bowl members, sometimes referred to in the art as bowl stages,  532 ,  534 . Each bowl member  532 ,  534  comprises a hollow diffuser member  533 ,  535 . The diffuser members each have vanes projecting inwardly from an outer shell/housing portion. Each bowl member  532 ,  534  also comprises an impeller member  536 ,  538 , having one or more rotating blades. Each impeller member  536 ,  538  is rotatable relative to the associated diffuser member  533 ,  535  by a solid driveshaft  540 . The driveshaft  540  extends through the bowl assembly  530  and tubular well column  512  and is operable attached to the turbine-pump motor  514  at the top of the well column  512 . 
     The turbine-pump motor/generator  514  is typically positioned above ground level  520 . A bowl skirt  542  generally forms the lower end of the bowl assembly  530  and is positioned below the water level  521  in the vertical well enclosure  550 . Well water enters the bowl assembly  530  through an opening  544  in the bowl skirt  542 . The well column  512  is attached in sealed relationship with the bowl assembly  530  and has a bottom opening in fluid communication with an upper opening of the bowl assembly  530 . 
     Rotation of the driveshaft  540  rotates the attached impellers  532 ,  534  causing water to be raised up through the bowl assembly  530  and through the attached well column  512 . The stationary diffusers members  533 ,  535  operate in cooperation with the rotating impeller members  536 ,  538  to create an upward flow of water through the bowl assembly  530  and well column  512 . Well water is typically pumped through an opening  522  at the upper end  524  of the well column  512  and into a horizontally disposed pipeline. The pipeline may ultimately discharges into a water reservoir (not shown) located on or near the surface  520 . 
     The pump column  512  may be vertically supported near its upper end  524  by an annular fixed plate  526 , or the like, which may in turn be attached to a concrete pad (not shown) located near the top of the well casing  552 . Thus, the pump column  512  remains stationary as the driveshaft  540  rotates within it. The pump column  512  may comprise a number of axial sections  562 ,  564 ,  566  that are bolted together or otherwise connected. The driveshaft  540  may also comprise a plurality of axial sections  572 ,  574 ,  576  attached by couplings  571 ,  573 . Bearing assemblies  575 ,  577 , attached to the well column  512 , may be used to support the driveshaft  540  radially and axially. 
     When the water level  521  in the well falls below the level of the bowl assembly skirt  542 , additional axial sections must be added to the well column and additional axial sections must be added to the driveshaft. With major water level declines, this involves pulling the entire pump column  512  and the entire drive shaft  540  out of the well casing  552 . The bowl assembly is then removed from the pump column and a new section of pump column is attached between the existing lower end of the pump column and the bowl assembly  530 . A similar operation is performed to install a new section to the drive shaft  540  between the existing end thereof and the portion of the drive shaft in the bowl assembly  330 . The pump column  552  is extremely heavy and thus requires an expensive heavy crane or the like for the removal and reinsertion operation. 
     In applications of the vertical turbine-pump  510 , water from a surface reservoir (not shown) may be injected through inlet  522  causing the drive shaft of the vertical turbine-pump assembly  510  to rotate in a direction opposite to the direction of rotation when the assembly  510  functions as a pump. Thus, during water injection the turbine-pump assembly  510  rotates the electric motor thereof in an opposite direction to produce electricity, which may be conventionally transferred to an electrical grid. 
       FIGS. 2A and 2B  schematically illustrate a turbine-pump system  10  that includes a driver  20  that may be located at ground level  52  to provide a reliable and readily accessible power supply. The driver  20  may be, for example, a vertical shaft electric motor  21  (that may be operated in a reverse direction as a generator) or a right angle drive unit  23  (shown in dashed lines), that may be an engine, turbine, or other drive means. If a turbine is used for drive unit  23  is used it could be a steam powered turbine or a combustion turbine. Such drive sources are capable of producing a high power output (e.g. 10,000 hp. or more), which is needed for high volume pumping of water from extremely deep, e.g., 10,000 ft., wells. Large load-bearing axial thrust bearings  30 , which may be positioned above ground level  52 , connect the motor assembly  20  to a hollow driveshaft  60 , as described in further detail below. 
     Existing or new well casing  40 , which in some embodiments is about 6 in. to 36 in. in internal diameter, extends axially along an excavated well shaft  41 . In some embodiments there is a space between the surface of excavated well shaft  41  and the outer surface of the well casing which is backfilled or filled with other material  39 . (Well casing and the manner in which it is installed in a well excavation are known in the art and are thus not further described herein.) The well casing  40  defines a cylindrical well enclosure  43  through which water  50  at the bottom of the well is pumped to the surface  52 . Use of the well casing  40  as the conduit for transmitting water eliminates the need for an expensive, heavy well column of the type described above with reference to prior art well column  512 . The larger cross section of a well casing cavity compared to that of a well column (column pipe) facilitates efficient, relatively low friction water flow, as compared to the water flow through a well casing with a smaller cross section. Portions of the turbine-pump system  10  are supported and stabilized by inflatable packers  82 ,  84  that engage an interior wall surface  42  of the well casing  40 , as described in further detail below. 
     A hollow mechanical driveshaft  60  transfers mechanical energy from the driver  20  to multiple impeller members (e.g.  370 ,  380 ,  FIG. 3A , not shown in  FIGS. 2A and 2B ) within each of a plurality of “bowl assemblies,” e.g.,  70 A,  70 B,  FIGS. 2A and 2B . A “bowl assembly,” e.g.  70 A, includes a “diffuser subassembly” and a corresponding “impeller subassembly,” as well as other components. As used herein, a “diffuser member” refers to a separate, stationary structure that operates in combination with a rotating “impeller member” to create water flow through the turbine-pump system  10 . 
     Each diffuser member  74 ,  75 ,  76 , typically has an impeller member, (e.g.,  370  in  FIG. 3A , not shown in  FIGS. 2A and 2B ) operatively associated with it. The diffuser member is positioned in axially and radially fixed relationship within the well casing  40 . The drive shaft  60  extends through each diffuser member  74 ,  75 ,  76 . An impeller member associated with a diffuser member is fixedly attached to the driveshaft  60  and rotates with the driveshaft  60 . The associated diffuser member does not rotate with the drive shaft  60 . In other words, the driveshaft  60  and impeller member  370   FIG. 3A ) attached thereto rotate inside an associated fixed diffuser member  74 ,  75 ,  76 . 
     The driveshaft  60  is constructed of a size and strength sufficient to handle the torque and axial loading created by the associated turbine-pump system  10 . The driveshaft  60  may be a customized oil field shouldered drill pipe construction. An axial internal passageway  62  (sometimes referred to herein as “working fluid passage  62 ” or simply “passage  62 ”) of the hollow driveshaft  60  enables the flow of working fluid used for inflating down-hole packers  82 ,  84  that form a part of each bowl assembly  70 A,  70 B. The passage  62  also enables this same working fluid to be provided to bearings (not shown in  FIGS. 2A and 2B ) that are positioned along the hollow driveshaft  60 . The hollow driveshaft  60  has an upper end portion  61  coupled to the driver  20 . The working fluid used to inflate the packers  80  and lubricate the bearings (not shown in  FIGS. 2A and 2B ) may be water or oil or a water and oil mixture or other liquid, which is stored in a pressurized liquid supply (not shown) and pumped with pump  90  through a small conduit  92  and a rotary union  94  into the hollow driveshaft passage  62 . The internal passageway  62  is sealed at the lowermost end of the hollow driveshaft  60 , enabling the working fluid to be pressurized. 
     The hollow driveshaft  60  because of its relatively large annular cross-section may withstand higher torques than a solid driveshaft with the same mass. Use of a high torque driveshaft enables the use of high torque impellers that may be operated at lower rotational speeds to produce the same water flow as high speed/low torque impellers. It also enables the use of very large, high power drive units that would destroy a solid shaft of the same mass. The hollow driveshaft  60  also enables a modular construction in which each module comprises a bowl assembly. Each bowl assembly may comprise a diffuser subassembly, an impeller subassembly that is rotated by an associated portion of hollow drive shaft and a packer assembly. The hollow drive shaft  60  may comprise separate lengths of drill pipe, which may have standard threaded ends and which may thus be quickly and easily connected by standard drill pipe connections. The driveshaft/diffuser member/impeller member mounting arrangement is described in detail with reference to  FIGS. 3A and 3B  below. The external and internal diameters of the drive shaft  60  will be determined by the torque that it must withstand, the size of internal passage needed for transmitting working fluid, etc. 
     The bowl assemblies  70 A,  70 B may be spaced throughout the axial length of the casing  40  at intervals. In some embodiments the spacing intervals are between about 200 ft. and 500 ft. (It will be understood that  FIGS. 2A and 2B  are schematic and that many such bowl/diffuser assemblies may be required depending upon the depth of the well.) Each bowl assembly, e.g.,  70 A is held in sealed, fixed relationship with an associated length of well casing by a packer, e.g.,  84  that forms a portion of the bowl assembly. 
     Well water  50  is drawn in through an inlet portion opening  79  of conduit or sleeve  78  that forms the bottom end of the lower most bowl assembly  70 B. The inlet opening  79  is positioned below the surface level of the well water  50 . The rotation of impeller members (described in detail below with reference to  FIGS. 3A and 3B ) in the lower assembly  70 B raises the water through each diffuser member,  76 ,  75 ,  74  and out the discharge end  69  of the bowl assembly  70 B. Then the water moves through a portion of the casing enclosure  43  to the next bowl assembly  70 A. All of the water that eventually reaches the surface flows through each bowl assembly  70 A,  70 B because the associated packer, e.g.  84 , seals off the annular region between the bowl assembly  70 B and the casing  40 , thus preventing water from flowing around the associated bowl assembly. The water is progressively lifted in this manner from one bowl assembly  70 B to the next bowl assembly  70 A to the upper portion of the well casing  40  where it may be discharged through conduit  63  at or near the surface  52 . 
     The description immediately above is a description of operation of the turbine-pump system  10  in a pump operating mode. In a turbine operating mode of the system  10 , water from a surface reservoir or other source (not shown) is injected into the well casing through conduit  63 . The water flows downwardly through the well casing and each bowl assembly, causing the impeller subassemblies in each bowl assembly to rotate in a reverse direction from that when the system  10  is in the pump operating mode. In the turbine operating mode the rotation of the impellers by the descending water flow provides torque to the hollow drive shaft  60  that is transmitted to the motor/generator  21  attached thereto. The motor/generator  21  is thus rotated in a generator mode to produce electricity, which may be transferred by electric cables  96  to a connected electric grid (not shown). 
     The use of multiple bowl assemblies allows for reasonable pressure differentials across each bowl assembly  70 A,  70 B. In conventional As mentioned above, each bowl assembly  70 A,  70 B in the illustrate embodiment of  FIGS. 2A and 2B  has the lower end thereof held and sealed against the well casing  40  by an associated bowl assembly end packer, e.g.,  84 . Each of these bowl assembly end packers  82 ,  84  has an internal conduit member, e.g.  78  that is connected in fluid communication with a lower end of a lower diffuser member, e.g.  76  in each bowl assembly, e.g.,  70 B. In another embodiment, not shown, the end packers  82 ,  84  are positioned at the upper ends of the associated bowl assemblies  70 A,  70 B, rather than at the lower ends. 
     The frictional engagement of the bowl assembly end packers  82 ,  84  with the well casing surface  42  vertically supports the associated bowl assembly  70 A or  70 B, etc., and prevents the associated diffuser subassembly  70 A or  70 B from rotating. Diffuser packers  82 ,  84 , etc., also seal off the annular space between each bowl assembly  70 A,  70 B and the inside surface  42  of the well casing  40 . Thus, water flows through the diffuser assemblies rather than around them. Conventional bearings (e.g.  392  and  358  shown in  FIGS. 3A and 3B ) within each bowl assembly  70 A,  70 B support the hollow driveshaft  60  and enable it to resist radial and axial forces. The radial and axial forces generated at each set of bearings are relatively low because of the multiple driveshaft support bearings that are provided, i.e. one or more axial and radial bearing assembly may be provided for each bowl assembly packer  82 ,  84 . 
     Depending upon the distance between bowl assemblies  70 A,  70 B and the stiffness of the driveshaft  60 , intermediate bearing assemblies  110 A and  1108 , held in position by intermediate packers  112 A and  112 B may be used to provide additional support to the driveshaft  60 . 
     In another embodiment, each bowl assembly  70 A,  70 B, etc. has few fewer individual diffuser members  74 ,  75 ,  76  and the bowl assemblies  70 A,  70 B, etc., are spaced more closely, for example 60 to 120 ft. apart. In such an arrangement no intermediate bearing assemblies may be needed. The bowl assemblies  70 A,  70 B described above with reference to  FIGS. 2A and 2B  may have the same construction as the bowl assemblies used in the centrifugal pump  200  of  FIG. 3B , described below, except that in  FIGS. 3A and 3B , each bowl assembly has two rather than three diffuser members. 
       FIGS. 3A and 3B  show a centrifugal turbine-pump  200  positioned in a vertical cylindrical space  202  defined by a conduit such as a well casing  204 . A bowl assembly  206  defines a portion of a water flow path  208  through the vertical cylindrical space  202 . The bowl assembly  206  has an inlet sleeve portion  296  providing a water inlet  212  at its lower end. The bowl assembly  206  has an outlet sleeve  209  defining a water flow outlet portion  214 . 
     An elongate hollow driveshaft assembly  230  extends longitudinally through a center portion of the bowl assembly  206 . The hollow driveshaft assembly  230  defines a continuous working fluid passage  232 , which extends through the entire length of the driveshaft assembly  230  and is closed at the bottom end thereof (not shown). 
     The hollow driveshaft assembly  230  is a rotating portion of the bowl assembly  206 . The driveshaft assembly  230  includes a first externally extending conduit, which in one embodiment is a conventional oil well drill pipe  234 . The drill pipe  234  may have an expanded threaded end portion  236 . An inlet coupling member  238  may have threaded end portions  242 ,  244 . The coupling member  238  connects the external drill pipe  234  to a first internal hollow drive shaft length  246  at a first threaded end portion  248  thereof. The first internal hollow drive shaft length  246  has a threaded second end portion  252 ,  FIG. 3A , positioned in alignment with a second internal hollow drive shaft length  254  that has a first threaded end portion  256  and a second threaded and portion  258 . A threaded coupling member  260  has internal threads  262  at a first end thereof and internal threads  264  at a second end thereof, which connect the first and second internal hollow drive shaft lengths  246 ,  254 . The threaded coupling member  260  also has external threads  266 , used to attach an impeller member, as described in further detail below. Another coupling member  270  that may be of identical construction to the threaded coupling member  260 , is attached to the second threaded end portion  258  of the second internal hollow drive shaft length  254  at a first threaded end portion  256  thereof. A third internal hollow drive shaft length  274  having a first threaded end portion  276  and a second threaded end portion  278  is attached to the second internal hollow drive shaft length  254  by the coupling member  270 . The second threaded end  278  of the third internal hollow drive shaft length  274  projects outwardly from an outlet sleeve portion of the bowl assembly  206 . An outlet end coupling member  280  having a first threaded end portion  282  and a second threaded end portion  284  attaches the third internal hollow drive shaft length  274  to an upper end external drill pipe  288 , which may have an expanded threaded end portion  290 . Thus the hollow driveshaft assembly  230  that forms a portion of the bowl assembly  206  in the illustrated embodiment of  FIGS. 3A and 3B  includes multiple pipe portions and annular coupling members that define a fluid passageway for working fluid that extends from one end of the bowl assembly  200  to the other. 
     An annular axial and radial thrust bearing assembly  292  may be mounted on a lower end portion of the first internal hollow drive shaft length  246 . The annular bearing assembly  292  supports the hollow driveshaft assembly  230  both axially and radially while enabling rotation of the driveshaft  230  assembly relative to a diffuser subassembly of the bowl assembly  206 . The annular bearing assembly  292  is attached, as by struts  294  to an annular lower sleeve portion  296  of the elongate housing  206 . Annular bearing assembly  292  comprises a rotary fluid seal assembly  298 . The Rotary fluid seal assembly  298  maintains a sealed, controlled leakage relationship with the outer surface of drill pipe  246  while enabling rotational movement of the drill pipe  246  within the seal assembly  298 . Working fluid in the internal passage  232 , passes through radially extending bores  299  to an annular reservoir (not shown) of the annular seal assembly  292 . The working fluid is transmitted through this annular reservoir in the fluid seal assembly  298  to the annular bearing assembly  292 . The working fluid, which in some embodiments is oil or water or the combination of oil and water, is used to lubricate the bearing assembly  298 . The controlled leakage of working fluid from the seal assembly  298  ensures a continuous supply of clean working fluid to the bearings and also ensures that the release of pressure at the surface will enable the packers to deflate. Bearing assemblies, such as annular bearing assembly  292  and the associated rotary fluid seal assembly  298 , are known in the art and are thus not further described herein. 
     An annular inflatable packer assembly  310  having a lower end portion  311  and an upper end portion  313  is integrally or otherwise fixedly attached to the housing lower sleeve portion  296 . The packer assembly  310  includes an annular inner wall  312  that defines a portion of the fluid path  208 . An annular outer packer wall  313 , having an annular central opening  315 - 315  (i.e. the opening is positioned between axial locations  315  and  315 ), is positioned radially outwardly of the inner packer wall  312 . The outer packer wall  313  has an expandable bladder  316  operably attached thereto. The bladder  316  may be expanded through opening  315 - 315  into engagement with the annular inner wall of the well casing  204  as shown in dashed lines. A rotary bearing seal assembly  320  is sealingly rotatable mounted on the drill pipe  246  at a position axially spaced from and above the lower rotary seal assembly  292 . This rotary seal assembly  320  receives working fluid from the hollow driveshaft fluid passage  232  through radial bores  322  and transmits the working fluid to the inflatable bladder  316  via a radial conduit  324 . The packer bladder  316  is thus in fluid communication with the fluid passage  232  and remains inflated so long as the working fluid remains pressurized. Reduction of the working fluid pressure allows the packer bladder  316  to deflate, enabling axial movement of the centrifugal pump  200  within the well casing  204 . 
     The bowl assembly diffuser subassembly includes a first annular diffuser member  326  that is attached at a first end portion  328  thereof to the packer assembly  310  as by threading (not shown) or other attachment means. The first annular diffuser  326  has a generally concave shaped body portion  330 , which ends in a threaded second end portion  332 . A second annular diffuser member  340  having a first threaded end  342 , a concave body portion  344  and a second threaded end portion  346  is threadingly attached to the first annular diffuser member  326 . A third annular diffuser member  350  has a first threaded end portion  352  that is threadingly attached to the second threaded end portion  346  of the second annular diffuser member  340 . The second annular diffuser member  340  has a free end that is radially spaced from an associated impeller member  384 . A rotary bearing  358  is rotatably mounted on the third internal hollow drive shaft length  274  and may be held in fixed relationship with the diffuser subassembly as by struts  359 . It may be seen from  FIG. 3A  that the connected first second and third annular diffuser members  326 ,  340  and  350 , sometimes referred to as a diffuser subassembly, have a generally sinusoidal cross-section. An annular upper sleeve member  356  may be an axial extension of the second diffuser member  340 . Sleeve member  356  defines an outlet of the bowl assembly  206 . 
     As shown by  FIG. 3A , a first annular impeller member  370  has a first end portion, terminating at  373 , that is threaded onto an outer threaded portion of coupling  260 . This threaded attachment holds the first impeller member  370  in coaxial, fixed relationship with the elongate hollow shaft assembly  230 . Thus, the impeller member  370  rotates with the hollow shaft assembly  230 . The impeller member  370 , in one embodiment, is a mixed flow, open or semi open impeller member. The cross section of the first annular impeller member  370  has a generally convex shaped body portion  384  that generally conforms to the shape of the associated diffuser body portion. A second annular impeller member  380  has a first threaded annular end portion  382  threaded to coupling  270  that engages the second end portion  376  of the first impeller member  370  and also engages a circumferential portion of the internal hollow drive shaft length  254 . The second impeller  380  has a convex body portion  384  and a second end portion  386  that engages an annular portion of drill pipe  274 . 
     As shown in  FIGS. 3A and 4 , the first annular impeller member  370  includes the convex shaped body portion  384  and a plurality of impeller blades B projecting outwardly therefrom. Each impeller blade B has an axial length shorter than a length of it&#39;s associated convex shaped body portion  384 . For example, the axial length of the blade can be about half the length of the convex shaped body portion  384 . As also shown in  FIGS. 3A and 4 , the second annular diffuser member  340  includes a plurality of vanes V projecting inwardly from the concave body portion  344 . 
     The attached first and second annular impeller members  370 ,  380 , like the diffuser members  326 ,  340 ,  350 , have an axially abutting configuration, and also have a generally sinusoidal cross-sectional shape.  FIG. 4  is an axial cross-sectional view showing the relationship of an impeller member, e.g., impeller member  370 , with an associated diffuser member, e.g. diffuser member  326 . The annular impeller members  370 ,  380  and annular diffuser members  326 ,  340 ,  350  define a continuous axial passageway  354 , which provides a portion of the fluid flow path through the bowl assembly  200 . 
     As with the turbine-pump system described with reference to  FIGS. 2A and 2B , the bowl assembly  200  may or may not be one of a series of identical bowl assemblies that are held within a conduit by a packer assembly  310  portion of the bowl assembly  200 . The plurality of identical bowl assemblies  200  may each comprise a driveshaft assembly portion  230 . These identical bowl assemblies  200  may each provide a turbine-pump system module. These modules may be connected to other modules that are connected by an upper module to a motor/generator  20 , such as described with reference to  FIGS. 2A  and  2 B. This modular construction facilitates the construction of a turbine-pump system because the modules can each be assembled at a warehouse facility and then transported to a well site and coupled together one at a time as each module is inserted into a well casing or other conduit. These modules are relatively light as compared to a pump column. Also, because each module supports its own weight within the well casing by means of its associated packer assembly there is virtually no limit to the well depth in which such a turbine-pump system may be deployed. 
     Another embodiment of a centrifugal pump  400  in which the impeller members themselves function as portions of a hollow drive shaft is illustrated in  FIG. 4 . A well casing  401  defines a cylindrical well cavity  402 . A bowl assembly  404 , positioned in the well cavity  402  comprises a diffuser subassembly that includes first, second and third diffuser members  406 ,  408 ,  410 . Each diffuser member has a first threaded end portion  412  and a second threaded end portion  414 . 
     An impeller subassembly  420  is operatively associated with the bowl assembly  404 . The impeller subassembly  420  comprises first, second and third impeller members  422 ,  424 ,  426 . Each impeller member has a first threaded end portion  428  and a second threaded end portion  430 . In this embodiment the first and last impeller member in the impeller subassembly are each attached, at one end portion thereof, to an upper and lower hollow driveshaft portion, such as a drill pipe (not shown). However there are no intermediate drill pipes or coupling members connecting the impeller stages  422 ,  424 ,  426 . Instead, the first threaded end portion  428  of each impeller member is connected to the second threaded end portions  430  of adjacent impeller member. 
     It may be seen from  FIG. 4  that an internal cavity  432 ,  434 ,  436  of each annular impeller member  422 ,  424 ,  426  provides a portion of a continuous axial passageway  438 , which is also formed in part by connected pipe members, such as oil well drill pipe (not shown). Thus, in this embodiment the impeller subassembly  422 ,  424 ,  426  and the connected drill pipes (not shown) are each portions of a hollow drive shaft assembly that rotates the impeller members and provides a working fluid passage for inflating an associated inflatable packer (not shown in  FIG. 4 ) and for lubricating associated bearing assemblies (not shown in  FIG. 4 ). In other words, the working fluid that in other embodiments is transmitted exclusively through internal passages in pipe and hollow couplings, is, in this embodiment transmitted through each impeller subassembly by the internal cavities in the impeller members. Similarly, the torque transmitted from or to a connected driver, e.g., driver  20  of  FIG. 2A , to each impeller member, is now transmitted in each bowl assembly, exclusively by each impeller member to the adjacent impeller member with no intervening structure. 
     Although in the above described embodiments, impeller members and diffuser members are shown attached by threading, it will also be understood by those with skill in the art that such attachment could be made by other means, for example by interlocking slotted and keyed portions or various other attachment means known in the art. In some cases, such as in the use of threaded portions, this attachment will be readily detachable, in others, at least some of the attachments may be of a more permanent nature, such as welded or soldered attachments. 
     It will be appreciated from the above disclosure that a method of moving liquid through a well conduit may include providing at least one bowl assembly having an impeller subassembly and a diffuser subassembly. The method may also include nonrotatably supporting the diffuser subassembly at a desired axial position within the well conduit with a packer. 
     It will be also be appreciated from the above disclosure that a method of moving well liquid through a sell conduit may include fixedly mounting a plurality of bowl assemblies with impeller subassemblies therein in axially spaced apart relationship within the well conduit. The method may also include rotating all of the impeller subassemblies in the plurality of bowl assemblies with a single rotary driver. 
     Various embodiments of centrifugal turbine-pump systems and bowl assemblies thereof are expressly disclosed in detail herein. Alternative embodiments of such systems and assemblies will occur to those in the art after reading this disclosure. It is intended that the claims be construed broadly to cover such alternative embodiments, except as limited by the prior art.