Abstract:
A helical turbine configured to rotate transversely within a cylindrical pipe under the power of fluid flowing either direction therethrough is operatively coupled with a rotating machine or generator to produce work or electricity. The twisted blades of the turbine define a right circular cylinder when the shaft mounting them rotates under the influence of fluid flow through the pipe. In one embodiment, baffles are provided at least upstream of the cylindrical turbine and within the cylindrical pipe to control flow through the cylindrical turbine. The twisted blades of the helical turbine are airfoil in cross section, as are the radial struts or spokes that mount the twisted blades to the rotatable shaft, thereby to optimize hydrodynamic flow, to minimize cavitation, and to maximize conversion from axial to rotating energy.

Description:
RELATED APPLICATIONS 
       [0001]    This is a continuation-in-part of and claims the benefit of priority from U.S. patent application Ser. No. 12/384,765 filed Apr. 7, 2009, the contents of which are incorporated herein in their entirety by this reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to the field of hydro-electric power generation. More particularly, the invention relates to hydro-electric power generation via fluid flow past a turbine. 
       BACKGROUND OF THE INVENTION 
       [0003]    U.S. Pat. Nos. 5,451,137; 5,642,984; 6,036,443; 6,155,892; 6,253,700 B1; and 6,293,835 B2 to Gorlov disclose various cylindrical turbines for power systems, the blades of the turbines extending helically to sweep out an open cylinder. The patents disclose mounting such turbines in rectangular and/or square cross-sectional channels or ducts capable of conveying water that rotates the turbines to generate hydro-electric power. Gorlov&#39;s cylindrical turbine has helically curved/twisted blades or vanes mounted to a central shaft by radial struts or spokes of seemingly arbitrary or at least non-airfoil, e.g. circular, cross section. PCT/US00/35471 describes and illustrates a cylindrical turbine having helically twisted blades each with airfoil cross sections of variable sizes along their extents. Each twisted blade is mounted to a central rotating hub by a blade support member also having an airfoil cross section. Two or more radial blades “uniformly distributed” on some or all of the twisted blades make use of deviated transverse flow in an axial direction parallel with the turbine&#39;s shaft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is an isometric exploded assembly drawing of a first embodiment of the invention featuring an un-baffled cylindrical turbine. 
           [0005]      FIG. 2  is a front elevation of the assembled first embodiment. 
           [0006]      FIG. 3  is an isometric exploded assembly drawing of a second embodiment of the invention featuring a baffled cylindrical turbine. 
           [0007]      FIG. 4  is a side elevation of the assembled second embodiment. 
           [0008]      FIG. 5  is an isometric exploded assembly drawing of the cylindrical turbine of  FIG. 1 . 
           [0009]      FIG. 6  is an isometric view of the assembled cylindrical turbine. 
       
    
    
       [0010]    Details A and B are fragmentary side elevations of the turbine-containing pipe of  FIG. 1  showing a side-by-side comparison of two different embodiments of the circular plate shown therein. Specifically, Detail A shows a flat circular plate and Detail B shows a spherically concave circular plate for mounting a proximal end of the turbine&#39;s shaft. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0011]      FIG. 1  is an isometric exploded assembly drawing of a first embodiment of the invented in-pipe hydro-electric power system  10  featuring an un-baffled cylindrical turbine. System  10  in accordance with one embodiment of the invention includes a T-section fluid (broadly encompassing a liquid such as water or a gas such as air or the like material exhibiting useful flow characteristics) pipe  12 , a bulkhead or generator assembly  14 , and a cylindrical turbine assembly  16 . Those of skill in the art will appreciate, by brief reference to  FIG. 2 , that when assembled and driven by fluid flow through pipe  12 , turbine assembly  16  rotates and system  10  produces hydro-electric power that can be stored, consumed, or fed into a power grid. 
         [0012]    Pipe  12  is generally cylindrical, having a generally circular cross section, although within the spirit and scope of the invention it can be slightly oval in cross section. Pipe  12  typically is a part of a longer and perhaps more complex fluid conveyance or pipe system, and it will be appreciated that an existing pipe system can readily be retrofitted with invented power system  10  by sectioning and replacing the removed section with power system  10 . Thus, pipe  12  is equipped with circular flanges  12   a  and  12   b  for bolting on either end to upstream and downstream pipe ends (not shown). Pipe  12  is provided with a small opening  12   c  in a first region of the sidewall and a large opening  12   d  in a diametrically opposed region thereof. As will be seen, small opening  12   c  accommodates a shaft of the turbine therethrough, while large opening  12   d  accommodates turbine assembly  16  therethrough. Pipe  12  also is equipped with a flanged T-intersection pipe section (a so-called “tee”) that effectively mates with large opening  12   d  at a right angle to the long axis of pipe  12 . 
         [0013]    Generator cap assembly  14  includes a circular arched plate  18  that effectively acts to close larger opening  12   d  when system  10  is assembled. Arched plate  18  provides a contiguous round wall inside pipe  12  for the fluid to flow past, thereby avoiding cavitation or other smooth fluid flow disruption within what would otherwise act as a pocket volume within the tee section. A 3-vaned, cylindrical spacer  20  holds arched plate  18  in place within the tee section when a cover plate  22  including an annular seal  22   a  and a circular plate  22   b  is bolted onto flange  12   e . Circular plate  22   b  has an opening  22   ba  therein with a mounting block  24  extending therearound. A first mount  26  including a roller bearing assembly mounts a proximal end of the shaft of turbine assembly  16  for smooth rotation therethrough. A flat shim  22   bb  can be provided between mounting block  24  and circular plate  22   b.    
         [0014]    A generator sub-assembly  28  bolts through a circular hole arrangement within circular plate  22   b . Generator sub-assembly  28  includes an annular spacer or standoff  30  for housing a generator  32  couple-able with the turbine&#39;s shaft, an annular rim  34  with a first mechanical-lift tab  34   a , and a cap  36  having a second mechanical-lift tab  36   a . Those of skill in the art will appreciate that tabs  34   a  and  36   a  provide convenient tabs for lifting all or part of the assembled tee-section electrical power generation components during assembly, disassembly, or maintenance. Those of skill will appreciate that the generator can be direct or alternating current (DC or AC) and single-phase or 3-phase, synchronized 120VAC or 240VAC, etc. and/or can be converted from one to the other, depending upon the power requirements. 
         [0015]    A mounting plate  12   f  is welded to pipe  12  around small opening  12   c  and a second mount  38  including a roller-bearing assembly that mounts a distal end of the shaft of turbine assembly  16  for smooth rotation therein. Those of skill in the art will appreciate that, to accommodate the circular cross section of cylindrical pipe  12 , first mount  26  in accordance with one embodiment of the invention includes a shim (not shown in pertinent detail but believed to be understood from this brief description by those of skill in the art) having an exterior planar surface and an inner cylindrical surface for mating with the exterior cylindrical surface of the pipe. The shim can be machined or formed by any suitable process and of any suitable material that ensures conformingly sealing engagement between the shaft and the pipe opening through which the shaft extends. Either shim described and/or illustrated herein will be understood to be optional, as either can readily be incorporated into the corresponding mounting block or plate. 
         [0016]    Finally, generator assembly  14  includes mounting plate  12   f  around small opening  12   c  of pipe  12  and a second mount  38  including a roller-bearing assembly that mounts a distal end of the shaft of turbine assembly  16  for smooth rotation therein. First and second mounts  26  and  38  can take alternative forms, within the spirit and scope of the invention, but it is believed that axial and radial thrust handling is best achieved using spherical roller bearings producing only rolling friction rather, for example, than sleeve bearings or other sliding friction arrangements. The roller bearing mounts described herein are believed to enable system  10  to operate safely, reliably and durably to produce electricity with a fluid flow rate through pipe  12  of as little as approximately 3-4 feet/second (fps). 
         [0017]    Those of skill in the art will appreciate that turbine assembly  16  is slipped through large opening  12   d  of pipe  12  and the proximal end of its shaft is secured to second mount  38 . Generator assembly  14  is bolted onto flange  12   e  of pipe  12  and the hydro-electric power system  10  is ready to operate. Power system  10  is fitted into or otherwise connected to a part of a pipe system (not shown). When fluid flows through pipe  12 , power system  10  generates electricity. 
         [0018]      FIG. 2  is a side elevation of assembled system  10 , and is believed to be largely self-explanatory. Those of skill in the art will appreciate that cylindrical turbine assembly  16  is generally square in cross section, while the interior of pipe  12  is generally circular in cross section. Thus, fluid within pipe  12  flows not only through turbine assembly  16  to cause it to rotate and to generate electricity via generator assembly  14 , but also around turbine assembly  16 , with little electricity generation effect. Nevertheless, efficient electricity generation is possible with the un-baffled cylindrical turbine system shown in  FIGS. 1 and 2 , since the cylindrical turbine assembly in accordance with the present invention has a relatively small cross-sectional ‘solidity’ (e.g. flow-restricting and energy-producing ratio between closed and total confronting surface area) effect on the flow of fluid therethrough. Importantly, as will be seen by reference to  FIGS. 5 and 6 , cylindrical turbine assembly  16  is an extremely efficient hydrofoil by virtue of an improved overall airfoil cross-sectional design of the blades that extend rectilinearly from a central, rotating shaft. 
         [0019]    Those of skill in the art will appreciate now that helically twisted and helically (or spirally) extending and cylindrically arcing blades of turbine assembly  16  ensure that a portion of at least one of the plural blades thereof is always optimally aligned with the flow of the fluid through pipe  12 . Indeed, in accordance with the embodiments of the invention described and illustrated herein, a portion of each of the plural blades thereof is always so optimally aligned. Moreover, all such portions of each blade present an extremely hydrodynamic airfoil cross section to the flowing fluid, thereby virtually eliminating undesirable cavitation. Surprisingly, it has been discovered that turbine assemblies such as those described and illustrated herein rotate at fluid flow rates as low as approximately 3-4 feet per second (fps). 
         [0020]      FIG. 3  is an isometric exploded assembly drawing of a second embodiment of the invented in-pipe hydro-electric power system  10 ′ featuring a baffled cylindrical turbine. System  10 ′ includes nearly all the component parts of system  10  in the same configuration but omits arched plate  18 , includes a higher spacer  20 ′, and includes a baffle assembly  40  that extends around turbine assembly  16  within pipe  12 . Those of skill in the art will appreciate that interiorly rectilinear and exteriorly curvilinear baffle assembly  40  effectively “squares the circle” within circular cross-sectional pipe  12 , thereby increasing and improving flow characteristics and electrical generation efficiencies with the cylindrical turbine embodiment of the invention. 
         [0021]    Those of skill in the art will appreciate from  FIG. 3  that four baffles  42 ,  44 ,  46 , and  48  are provided on one end of turbine assembly  16 , while four more baffles  50 ,  52 ,  54 , and  56  are provided on the other end thereof. The baffles are rectilinear in their interior or proximal regions to mate with a rectilinear (e.g. rectangular) open channel  58  (defined by four peripheral planar sidewalls) that surrounds turbine assembly  16 , while the baffles are curvilinear, e.g. parabolic, in their exterior or distal regions to mate with the interior of circularly cross-sectional cylindrical pipe  12 . Those of skill also will appreciate that the baffles and rectangular channel can be made of any suitable material, e.g. steel, and can be dimensioned and oriented for any desired fluid flow adjustment at either end. In accordance with one embodiment of the invention, each of baffles  42 - 56  is inclined relative to the long central axis of pipe  12  at an angle θ (refer briefly to  FIG. 4 ) of approximately 10 degrees. Other inclined angles are contemplated as being within the spirit and scope of the invention. (For example, incline angles θ of between approximately 5 degrees and 15 degrees can be used, although it will be understood that a more gradual incline may require a longer pipe  12  and a more abrupt incline may cause undue turbulence.) 
         [0022]    Thus, baffle assembly  40  can be described as a plurality of structural inserts that effectively narrows the cross section of the round pipe, each insert having a rectangular cross section transverse to the pipe, the inserts collectively smoothly directing essentially all of the fluid that would otherwise flow through the round pipe instead through the rectangular, e.g. square, cross-sectional turbine, i.e. within the turbine&#39;s perimeter. 
         [0023]    Those of skill in the art also will appreciate from  FIG. 3  (and also from  FIG. 4 ) that each of the eight baffles that form a part of baffle assembly  40  is equipped with a notch or vent  60  at its distal extremity, the notch creating a small opening between the baffles and their corresponding interior mating surfaces of cylindrical pipe  12 . These notches and the resulting openings provide fluid flow through pipe  12  exterior to baffle assembly  40 , thus filling what would otherwise be a void and providing a relatively static and stable fluid pressure outside the baffle assembly but within the pipe. The notches thus avoid incidental formation in that otherwise void region of pipe  12  of a no- or low-fluid-pressure condition that might otherwise undesirably stress or deform baffle assembly  40 . Thus, the notches may be referred to herein as pressure-equilibrium-promoting features. 
         [0024]    Those of skill in the art will appreciate that baffle assembly  40  may be thought of as having a so-called Venturi effect on the fluid flow through the pipe and thus on the rotation of turbine assembly  16 . By reducing the cross section of the pipe, the baffles effectively direct the fluid and increase its flow rate through the cylindrical turbine. It has been determined that flow rate increases significantly (and power thus even more significantly) through baffle assembly  40  over those typical fluid flow rates (e.g. approximately 15 fps) through configurations having no baffle assembly. 
         [0025]      FIG. 4  is a front elevation of assembled system  10 ′.  FIG. 4  is thought to be mostly self-explanatory based upon the description above regarding  FIG. 3  to which it corresponds. The angle θ of incline of the baffles can be more clearly seen, as can two of the four notches such as notch  60  (which for the sake of clarity is designated only once, although it will be understood that there are eight such notches in accordance with one embodiment of the invention). In accordance with this cylindrical-turbine embodiment of the invention, sufficient clearance around the rotating cylindrical turbine assembly and within the pipe is provided to avoid undue compression of fluid at the turbine sweep boundaries, as shown. 
         [0026]      FIG. 5  is an isometric exploded assembly drawing of cylindrical turbine assembly  16 . Cylindrical turbine assembly  16  includes an axially (linearly) toothed collar  62  having an inner diameter (ID) slightly greater than an outer diameter (OD) of a shaft  64  around which it extends and to which it is fixedly mounted via upper and lower split shaft couplers  66  and  68 . The toothed collar fixedly mounted via upper and lower couplers to the shaft may be collectively referred to herein simply as shaft  70 . 
         [0027]    Evenly arcuately spaced around and extending radially from shaft  70  are plural (e.g. three, in a so-called 180 degree vertical-axis, helical turbine) upper spokes  72 ,  74 , and  76 , and plural (e.g. three) lower spokes  78 ,  80 , and  82 . Those of skill in the art will appreciate that the upper and lower spokes are arcuately offset from one another by 60 degrees to mount corresponding plural (e.g. three) helically twisted and arcuately cylindrically extending turbine blades  84 ,  86 , and  88 . Corresponding with each of plural spokes  72 ,  74 ,  76 ,  78 ,  80 , and  82  is an inner hub  90 , an outer hub  92 , and a corner block  94  (which are designated only once in  FIG. 5  for the sake of clarity but which will be understood to number the same as the number of blades in the plurality). Those of skill in the art will appreciate that each of the plural airfoil blades mounted on or otherwise connected to or integral with a corresponding airfoil spoke is collectively referred to herein as a blade assembly. 
         [0028]    Those of skill in the art will appreciate that each of the plural inner blocks has a correspondingly axially (linearly) toothed inner arcuate surface for a secure grip on toothed collar  62 . It will also be appreciated that each of the blades (including the blade portion represented by the spokes) and the corresponding corner blocks have an airfoil cross section, e.g NACA  20  or any other suitable standard. Thus, the blades of cylindrical turbine assembly  16  are of uniformly sized and shaped airfoil cross section over their entire length and substantially all the way to the central shaft that mounts their termini. This represents a striking improvement over prior art helical turbines in which the disks, spokes or struts that mount the helically twisted and arcuate blades generally are not of airfoil cross section and are not of uniform cross sectional size and shape and thus thus are thought by some to cause undesirable cavitation and, more importantly, to lower hydro-electric power generation efficiency. Suitable fasteners such as hex bolts, lock washers, and set screws are used to assemble the component parts of cylindrical turbine assembly  16 , as illustrated. 
         [0029]    Those of skill in the art will appreciate that more or fewer than three blades can be used in cylindrical turbine assembly  16  in what is referred to herein as an arcuately spaced arrangement, i.e. a uniformly spaced arrangement around the turbine&#39;s cross-sectional circumference. For a three-blade cylindrical turbine, the blades may be seen from  FIGS. 5 and 6  to be spaced apart 120°, and each blade extends along an arcuate angle Φ of 60° helically around the cylindrical shape (or so-called “sweep”) of the rotating turbine. This three-blade arrangement and airfoil selection produces complete ‘overlap’ of the blades in cross-sectional view and a ‘solidity’ (i.e. the ratio of closed to open cross-sectional area within the pipe) of between approximately 15% and 20%. Those of skill will appreciate that the angle of blade inclination follows from the selected ratio of turbine diameter to height. 
         [0030]    Other airfoil configurations and/or other numbers and arrangements of the plurality of blades are contemplated as being within the spirit and scope of the invention. For example, a six-blade cylindrical turbine is contemplated, each blade having a smaller width, to produce a similar solidity configuration and to present smoother operation due to full overlap of the blades within the cylinder (a so-called 360° vertical-axis cylindrical turbine design). 
         [0031]      FIG. 6  is an isometric view of assembled cylindrical turbine assembly  16 .  FIG. 6  is believed to be largely self-explanatory in view of the detailed description above by reference to  FIG. 5 .  FIG. 6  perhaps better illustrates the angles and arrangements and helical curves and twists of the plurality of blades in cylindrical turbine assembly  16 . It will be appreciated that the angle of inclination of the blades—i.e. the angle of intersection of a plane in which lies each of the plurality of cylindrical turbine blades ( 84 ,  86 , and  88 ) and the central axis of the shaft in accordance with one embodiment of the invention—is approximately 30 degrees, although other helical angles are contemplated as being within the spirit and scope of the invention. 
         [0032]    An alternative to the above circular plate  22   b  is illustrated in Details A and B, which are fragmentary cut-away side elevations featuring the interior of tee section  12   e . Those of skill in the art will appreciate that absolute and relative dimensions in Details A and B are not to scale, as they are for general structural comparison purposes. 
         [0033]    A side-by-side comparison of Detail A, which features flat circular plate  22   b  described above, and Detail B, which features a spherically concave circular plate  22   b ′, reveals some important advantages of alternative plate  22   b ′. Flat circular plate  22   b  must be formed of relatively thick material, thereby rendering it heavy and difficult to handle. Spherically concave circular plate  22   b ′ on the other hand may be seen to be formed of relatively thin material, thereby rendering it significantly lighter in weight and significantly easier to handle. 
         [0034]    This is by virtue of the curvature of alternative plate  22   b′.    
         [0035]    Moreover, the central region of flat circular plate  22   b  may be seen to be farther from the turbine assembly, thus undesirably extending the length of the turbine&#39;s shaft. Conversely, the central region of spherically concave circular plate  22   b ′ may be seen to be closer to the turbine assembly, thereby desirably shortening the required length or vertical span of the turbine&#39;s shaft. 
         [0036]    This too is by virtue of the curvature of alternative plate  22   b′.    
         [0037]    From Detail B, concave plate  22   b ′ will be understood to be of generally spherical shape with the concavity extending inwardly from generator assembly (not shown for the sake of simplicity and clarity in this view) and toward the turbine assembly  16 ′ (shown only schematically in these detailed views by way of dash-dot-dot outlines, and the only difference from turbine assembly  16  being the provision of a shorter shaft  64 ′). This inward or downwardly oriented concave circular plate may be thought of and described herein as an inverted dome (or inverted cupola). While a spherically concave shape is illustrated and described, those of skill in the art will appreciate that suitable modifications can be made thereto without departing from the spirit and scope of the invention. For example, an inverted dome featuring a parabolic rather than a semi-circular cross section is possible, as are other curvilinear cross sections of various aspect ratios (i.e. of various depth-to-width ratios only one of which is shown with some intentional depth exaggeration for the sake of clarity). Also, the cupola-shaped plate in cross section can have a more rounded upper shoulder, producing what might be thought of as complex curvature. All such suitable alternative configurations are contemplated as being within the spirit and scope of the invention. 
         [0038]    Those of skill in the art will appreciate that mounting details in such an alternative embodiment are modified straightforwardly to accommodate inverted cupola-shaped circular plate  22   b ′ and its bolted assembly through annular seal  22   a  onto standard flange  12   e  of pipe  12 . For example, mounting block  24 ′ may include a shim  22   bb ′ that is spherically convexly curved to mate and seal the spherically concave curvature of the inside of the inverted cupola. A rotor or other moving part of generator  32  will be understood to mount to, for rotation with, the distal end of the turbine&#39;s shaft directly above the opening in the central region of spherical concave plate  22   b ′. Other components and techniques for accommodating alternative spherically concave circular plate  22   b ′ are contemplated as being within the spirit and scope of the invention. 
         [0039]    The embodiment illustrated herein is a three-blade cylindrical turbine assembly, but as few as two blades and as many as twenty blades are contemplated as being within the spirit and scope of the invention. More preferably, between approximately two and eleven blades are contemplated. Most preferably, between approximately three and seven blades are contemplated. Other numbers and configurations of helically arced cylindrical turbine blades are contemplated as being within the spirit and scope of the invention. Those of skill in the art will appreciate best perhaps from  FIG. 5  that the blades of the cylindrical turbine assembly are characterized along their entire length by airfoil cross sections. This provides the turbine&#39;s hydrodynamics and efficiency at generating hydro-electric power. In accordance with this cylindrical-turbine embodiment of the invention, sufficient clearance around the rotating cylindrical turbine assembly and within the pipe is provided to avoid undue compression of fluid at the turbine sweep boundaries (see  FIGS. 2 and 4 ). 
         [0040]    Those of skill will appreciate that the helical turbine blades, within the spirit and scope of the invention, can be made of any suitable material and by any suitable process. For example, the blades can be made of aluminum, a suitable composite, or a suitable reinforced plastic material. The blades can be made by rotational or injection molding, extrusion, pultrusion, bending, or other forming techniques consistent with the material used and consistent with the cost-effective production of elongated bodies having substantially constant cross sections. These and other useful materials and processes are contemplated as being within the spirit and scope of the invention. 
         [0041]    The dynamic sweep (central diameter) of the rotating cylindrical turbine assembly is greater than its static dimension (central diameter) due to centrifugal forces impinging on the turbine blades. This fact is accommodated by slightly under-sizing the cylindrical turbine relative to the ID of the pipe, e.g. by providing a small but preferably constant clearance of between approximately 0.5 centimeters and 5 centimeters and preferably between approximately 1 centimeter and 3 centimeters, depending upon the diameter of pipe  12  and other application specifics. These spacings are illustrative only, and are not intended to be limiting, as alternative spacings are contemplated as being within the spirit and scope of the invention. 
         [0042]    Surprisingly, it has been discovered that baffles  42 ,  44 ,  46 , and  48  near an upstream region of turbine assembly  16  can increase the electrical energy production by between approximately 14% and 40% and more likely between approximately 20% and 30% over the nominal output of the cylindrical turbine without such an upstream baffle assembly  40  within the pipe. 
         [0043]    Those of skill in the art will appreciate that the ratio between the baffles&#39; coverage and the turbine&#39;s sweep can be between approximately 10% and 40% and more likely between approximately 20% and 30%. Those of skill in the art will also appreciate that the amount of baffle coverage may be application specific, as it represents a tradeoff between volumetric flow rate and head drop-off. Thus, alternative ranges of baffle coverage and angle relative to turbine sweep are contemplated as being within the spirit and scope of the invention. 
         [0044]    Those of skill in the art will appreciate that the cylindrical turbine can serve in power conversion systems other than electric power generation. For example, axial kinetic energy of a fluid can be converted to rotating kinetic energy for any rotating machinery (e.g. a conveyor, a grinder, a drill, a saw, a mill, a flywheel, etc.) including an electric generator or the like (a like alternative, for example, includes an alternator, a magneto, and any other suitable mechanical-to-electric power conversion device). All such uses of the invented fluid turbine are contemplated as being within the spirit and scope of the invention. 
         [0045]    Those of skill in the art will appreciate that orientation of the invented system in its many embodiments is illustrative only and should not be read as a limitation of the scope of the invention. Thus, use of terms like upper and lower will be understood to be relative not absolute, and are interchangeable. In other words, the system can assume either vertical orientation, within the spirit and scope of the invention, with the bulkhead housing the generator and the turbine shaft extending relative to the long axis of the pipe either up or down. Indeed, the system can assume any other suitable angle in which the shaft of the turbine extends approximately perpendicular to the direction of the fluid flow. 
         [0046]    Those of skill in the art will appreciate that component parts of the invented systems can be made of any suitable material, including steel, aluminum, and polymers or other composites. Most parts can be steel, for example, as are the turbine shafts, flat plates, and baffles. Remaining parts including spokes, hubs, collars, coupling blocks, and blades can be made of machined, extruded, or pultruded aluminum (the blades then being roll-formed and/or twisted into the desired form) or of injection-molded, reinforced plastic or any other suitable polymer or composite (e.g. carbon or graphite). Any alternative material and any alternative forming process is contemplated as being within the spirit and scope of the invention. 
         [0047]    Those of skill will also appreciate that the invented systems are of easily scaled dimension up or down, depending upon their application. So that while dimensions generally are not given herein, dimensions will be understood to be proportionately accurately illustrated, the absolute scale of which can be varied, within the spirit and scope of the invention. 
         [0048]    Those of skill in the art will appreciate that two or more hydro-electric power generation systems can be installed at defined intervals (in series) within and along a fluid conveying pipe, thereby to multiply power generation. Those of skill in the art also will appreciate that parallel arrangements of two or more hydro-electric power generation systems can be installed within branches of a fluid conveying pipe, thereby alternatively or additionally to multiply power generation. Those of skill in the art will appreciate that kick-start mechanisms can be added to the hydro-electric power generation systems described and illustrated herein, if needed, for use of such systems in tidal (bidirectional, oscillating) flow applications. Those of skill will also appreciate that fail-safe modes of operation can be achieved in the use of the invented in-pipe hydro-electric power generation systems to prevent self-destruction in the event of bearing failure or the like. Finally, those of skill in the art will appreciate that such hydro-electric power generation systems as are described and illustrated herein can be placed within an exterior sleeve conduit that protects the power generation system from the elements and/or that facilitates power distribution along power cables or other suitable conveyances to nearby storage devices or power grids. 
         [0049]    It will be understood that the present invention is not limited to the method or detail of construction, fabrication, material, application or use described and illustrated herein. Indeed, any suitable variation of fabrication, use, or application is contemplated as an alternative embodiment, and thus is within the spirit and scope, of the invention. 
         [0050]    It is further intended that any other embodiments of the present invention that result from any changes in application or method of use or operation, configuration, method of manufacture, shape, size, or material, which are not specified within the detailed written description or illustrations contained herein yet would be understood by one skilled in the art, are within the scope of the present invention. 
         [0051]    Accordingly, while the present invention has been shown and described with reference to the foregoing embodiments of the invented apparatus, it will be apparent to those skilled in the art that other changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.