Note: Descriptions are shown in the official language in which they were submitted.
<br/> CA 02258419 1999-O1-08<br/> Title: PRANDTL LAYER TURBINE<br/> FIELD OF THE INVENTION<br/> This invention relates to an apparatus used to transmit<br/>motive force between a fluid and a plurality of spaced apart rotatable<br/>members. The apparatus may be used to transmit the motive force<br/>from a fluid to the spaced apart members or, alternately, from the<br/>spaced apart members to the fluid.<br/> BACKGROUND OF THE INVENTION<br/> Prandtl layer turbines were first described by Nikola Tesla<br/>in United States Patent No. 1,061,206 (Tesla). For this reason, these<br/>turbines are sometimes referred to as "Tesla Turbines". Figures 1 and 2<br/>show the design for a prandtl layer turbine as disclosed in Tesla. As<br/>disclosed by Tesla, a prandtl layer turbine 10 comprises a plurality of<br/>discs 12 which are rotatably mounted in a housing 14. Housing 14<br/>comprises ends 16 and ring 18 which extends longitudinally between<br/>ends 16. Discs 12 are spaced apart so as to transmit motive force<br/>between a fluid in housing 14 and rotating discs 12.<br/> The discs 12, which are flat rigid members of a suitable<br/>diameter, are non-rotatably mounted on a shaft 20 by being keyed to<br/>shaft 20 and are spaced apart by means of washers 28. The discs have<br/>openings 22 adjacent to shaft 20 and spokes 24 which may be<br/>substantially straight. Longitudinally extending ring 18 has a diameter<br/>which is slightly larger than that of discs 12. Extending between<br/>opening 22 and the outer diameter of disc 12 is the motive force<br/>transfer region 26.<br/> The transfer of motive force between rotating discs 12 and<br/>a fluid is described in Tesla at column 2, lines 30 - 49. According to this<br/>disclosure, fluid, by reason of its properties of adherence and viscosity,<br/>upon entering through inlets 30, and coming into contact with<br/>rotating discs 12, is taken hold of by the rotating discs and subjected to<br/>two forces, one acting tangentially in the direction of rotation and the<br/><br/> CA 02258419 1999-O1-08<br/>-2-<br/>other acting radially outwardly. The combined effect of these<br/>tangential and centrifugal forces is to propel the fluid with<br/>continuously increasing velocity in a spiral path until it reaches a<br/>suitable peripheral outlet from which it is ejected.<br/> Conversely, Tesla also disclosed introducing pressurized<br/>fluid via pipes 34 to inlets 32. The introduction of the pressurized fluid<br/>would cause discs 12 to rotate with the fluid travelling in a spiral path,<br/>with continuously diminishing velocity, until it reached central<br/>opening 22 which is in communication with inlet 30. Motive force is<br/>transmitted by the pressurized fluid to discs 12 to cause discs 12 to<br/>rotate and, accordingly, shaft 20 to rotate thus providing a source of<br/>motive force.<br/> Accordingly, the design described in Tesla may be used as a<br/>pump or as a motor. Such devices take advantage of the properties of a<br/>fluid when in contact with the rotating surface of the discs. If the discs<br/>are driven by the fluid, then as the fluid passes through the housing<br/>between the spaced apart discs, the movement of the fluid causes the<br/>discs to rotate thereby generating power which may be transmitted<br/>external to the housing via a shaft to provide motive force for various<br/>applications. Accordingly, such devices function as a motor.<br/> Conversely, if the fluid in the housing is essentially static, the rotation<br/>of the discs will cause the fluid in the housing to commence rotating<br/>in the same direction as the discs and to thus draw the fluid through<br/>the housing, thereby causing the apparatus to function as a pump or a<br/>fan. In this disclosure, all such devices, whether used as a motor or as a<br/>pump or fan, are referred to as "prandtl layer turbines" or "Tesla<br/>turbines".<br/> Various designs for prandtl layer turbines have been<br/>developed. These include those disclosed in United States Patent No.<br/>4,402,647 (Effenberger), United States Patent No. 4,218,177 (Robel),<br/> United States Patent No. 4,655,679 (Giacomel), United States Patent No.<br/><br/> CA 02258419 1999-O1-08<br/>-3-<br/>5,470,197 (Cafarelli) and United States Reissue Patent No. 28,742<br/>(Rafferty et al). Most of these disclosed improvements in the design of<br/>a Tesla turbine. However, despite these improvements, Tesla turbines<br/>have not been commonly used in commercial environment.<br/> SUMMARY OF THE INVENTION<br/> In accordance with the instant invention, there is<br/>provided an apparatus comprising:<br/>(a) a longitudinally extending housing having a fluid inlet<br/>port;<br/>(b) a plurality of spaced apart members rotatably mounted<br/>in the housing to transmit motive force between fluid<br/>introduced through the fluid inlet port and the members<br/>and to separate the fluid into at least two fluid streams;<br/>and,<br/>(c) a fluid outlet port positioned on the housing for<br/>receiving each fluid stream.<br/> In one embodiment, the fluid comprises at least two<br/>different constituent elements and the spaced apart members are<br/>configured to divide the fluid into a fluid stream for each outlet, each<br/>fluid stream having a different composition. The fluid may comprise<br/>at least two fluids of differing densities.<br/> In another embodiment, the fluid may include particles of<br/>varying sizes and the spaced apart members are configured to divide<br/>the fluid into a fluid stream for each outlet, each fluid stream having<br/>particles having a different particle size distribution. The apparatus<br/>may further comprise at least one cyclone in flow communication<br/>with one of the outlets wherein a respective fluid stream passes<br/>through the one of the outlets and then through the cyclone to at least<br/>partially separate the particles in the fluid stream from the fluid in the<br/>fluid stream. Alternately, the apparatus may further comprise a<br/><br/> CA 02258419 1999-O1-08<br/>-4-<br/>plurality of cyclones, each cyclone in flow communication with an<br/>outlet wherein a respective fluid stream passes through the outlet and<br/>then through the cyclone to at least partially separate the particles in<br/>the fluid stream from the fluid in the fluid stream.<br/> In another embodiment, the apparatus comprises a<br/>vacuum cleaner.<br/> In another embodiment, each spaced apart member has a<br/>pair of opposed surfaces extending between an inner edge and an outer<br/>edge and defining a motive force transfer region for transmitting<br/>motive force between the fluid and the spaced apart members, adjacent<br/>spaced apart members being separated by a longitudinally extending<br/>gap, the fluid forming a boundary layer as it passes over the spaced<br/>apart members, at least one of the following parameters of the spaced<br/>apart members being configured to assist in separating the fluid into at<br/>least two fluid streams, the at least one parameter selected from the<br/>group consisting of:<br/>(a) the longitudinally extending gap between adjacent<br/>spaced apart members;<br/>(b) the surface area of the motive force transfer region of<br/>the spaced apart members;<br/>(c) a raised area at at least one discrete location to increase<br/>the thickness of the boundary layer as it passes over the<br/>increased width at the discrete location;<br/>(d) a raised area at at least one discrete location to enhance<br/>the delamination of the boundary layer; and,<br/>(e) at least one fan member positioned in series with the<br/>spaced apart members.<br/> In another embodiment, the fluid outlet ports extend<br/>longitudinally along the housing and each have a first end positioned<br/>towards the upstream end of the spaced apart members and a second<br/>end positioned towards the downstream end of the spaced apart<br/><br/> CA 02258419 1999-O1-08<br/>-5-<br/>members, the second end of at least one of the fluid outlet ports<br/>radially displaced along the housing from the first end.<br/> In accordance with the instant invention, there is also<br/>provided an apparatus comprising:<br/>(a) a longitudinally extending housing having a means for<br/>permitting a fluid to enter the housing;<br/>(b) means for transmitting motive force between the fluid<br/>and a plurality of spaced apart means and separating the<br/>fluid into at least two fluid streams; and,<br/>(c) means for separately removing each fluid stream from<br/>the housing.<br/> In one embodiment, the apparatus further comprises at<br/>least one fluid/particle separation means in flow communication with<br/>one of the means for removing a fluid stream from the housing<br/>wherein a respective fluid stream passes through the one of the means<br/>for removing a fluid stream from the housing and then through the<br/>fluid/particle separation means to at least partially separate the<br/>particles in the fluid stream from the fluid in the fluid stream.<br/> In accordance with the instant invention, there is also<br/>provided a method comprising:<br/>(a) introducing a fluid into a housing having a plurality of<br/>spaced apart members rotatably mounted in the housing;<br/>(b) passing the fluid through the spaced apart members to<br/>form a boundary layer which passes over the spaced apart<br/>members;<br/>(c) dividing the fluid steam into at least two fluid streams<br/>as the fluid passes through the spaced apart members and<br/>separately withdrawing at least two fluid streams from the<br/>housing.<br/> In one embodiment, the fluid stream comprises at least<br/>two different constituent elements and the method further comprises<br/><br/> CA 02258419 1999-O1-08<br/>-6-<br/>withdrawing at least two fluid streams having different compositions<br/>from the housing. At least one of the fluid streams may be subjected to<br/>a separation step to produce a first stream having an increased<br/>concentration of one constituent element and a second stream having<br/>an increased concentration of a second constituent element.<br/> In another embodiment, the fluid stream comprises at<br/>least two different fluids and the method further comprises<br/>withdrawing at least two fluid streams having different compositions<br/>from the housing and subjecting at least one of the fluid streams to a<br/>separation step to produce a first stream having an increased<br/>concentration of one fluid and a second stream having an increased<br/>concentration of a fluid.<br/> In another embodiment, the fluid includes particles of<br/>varying sizes and the method further comprises withdrawing at least<br/>two fluid streams having different particle size distributions from the<br/>housing. At least one of the fluid streams may be subjected to a particle<br/>separation step to at least partially separate the particles in the at least<br/>one of the fluid streams from the fluid in the at least one of the fluid<br/>streams.<br/> BRIEF DESCRIPTION OF THE DRAWINGS<br/> These and other advantages of the instant invention will<br/>be more fully and particularly understood in connection with the<br/>following description of the preferred embodiments of the invention<br/>in which:<br/> Figure 1 is a cross section along the line 1 - 1 in Figure 2 of<br/>a prior art prandtl layer turbine;<br/> Figure 2 is a cross section along the line 2 - 2 in Figure 1 of<br/>the prior art prandtl layer turbine of Figure 1;<br/> Figure 3 is a top plan view of a disc according to a first<br/>preferred embodiment of the instant invention;<br/>..._..___._..w_ _...../ _. _<br/><br/> CA 02258419 1999-O1-08<br/>_7_<br/> Figure 4a is an side elevational view of the disc of Figure<br/>3;<br/> Figures 4b - 4d are enlargements of area A of Figure 4a;<br/> Figure 5 is a longitudinal cross section of a prandtl layer<br/>turbine according to a second preferred embodiment of the<br/>instant invention;<br/> Figure 6 is a schematic drawing of the spaced apart<br/>members of one of the prandtl layer turbine unit of Figure<br/>5;<br/> Figure 7 is a graph of suction and flow versus the ratio of<br/>the inner diameter of a spaced apart member to the outer<br/>diameter of the same spaced apart member;<br/> Figure 8 is a longitudinal cross section of a prandtl layer<br/>turbine according to a third preferred embodiment of the<br/>instant invention;<br/> Figure 9 is a longitudinal cross section of a prandtl layer<br/>turbine according to a fourth preferred embodiment of the<br/>instant invention;<br/> Figure 10 is a longitudinal cross section of a prandtl layer<br/>turbine according to a fifth preferred embodiment of the<br/>instant invention;<br/> Figure 11 is a longitudinal cross section of a prandtl layer<br/>turbine according to a sixth preferred embodiment of the<br/>instant invention;<br/> Figure 12a is a longitudinal cross section of a prandtl layer<br/>turbine according to a seventh preferred embodiment of<br/>the instant invention;<br/> Figure 12b is a cross section along the line 12 - 12 in Figure<br/>12a;<br/> Figure 13 is a longitudinal cross section of a prandtl layer<br/>turbine according to an eighth preferred embodiment of<br/><br/> CA 02258419 1999-O1-08<br/>_g_<br/>the instant invention;<br/> Figure 14 is a longitudinal cross section of a prandtl layer<br/>turbine according to a ninth preferred embodiment of the<br/>instant invention;<br/> Figure 15 is an end view from upstream end 78 of the<br/>prandtl layer turbine of Figure 14;<br/> Figure 16 is a longitudinal cross section of a prandtl layer<br/>turbine according to a tenth preferred embodiment of the<br/>instant invention;<br/> Figure 17 is an end view from upstream end 78 of the<br/>prandtl layer turbine of Figure 16;<br/> Figure 18 is a perspective view of a prandtl layer turbine<br/>according to an eleventh preferred embodiment of the<br/>instant invention;<br/> Figure 19 is a further perspective view of the prandtl layer<br/>turbine of Figure 18 wherein additional housing of the<br/>outlet is shown;<br/> Figure 20 is a perspective view of the longitudinally<br/>extending ring of a prandtl layer turbine according to an<br/>twelfth preferred embodiment of the instant invention;<br/> Figure 21 is a transverse cross section along the line 21 - 21<br/>of a prandtl layer turbine having the longitudinally<br/>extending ring of Figure 20 wherein the turbine has<br/>secondary cyclones in flow communication with the<br/>turbine outlets;<br/> Figure 22 is longitudinal section of a vacuum cleaner<br/>incorporating a prandtl layer turbine;<br/> Figure 23 is a longitudinal section of a mechanically<br/>coupled prandtl layer motor and a prandtl layer fan;<br/> Figure 24 is a perspective view of a windmill<br/>incorporating a prandtl layer turbine; and,<br/><br/> CA 02258419 1999-O1-08<br/>-9-<br/> Figure 25 is a cross section along the line 25 - 25 of the<br/>windmill of Figure 24.<br/> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT<br/> According to the instant invention, improvements to the<br/>design of prandtl layer turbines are disclosed. These improvements<br/>may be used in conjunction with any known designs of prandtl layer<br/>turbines. Without limiting the generality of the foregoing, housing 14<br/>may be of any particular configuration and mode of manufacture.<br/> Further, the fluid inlet and fluid outlet ports may be of any particular<br/>configuration known in the art and may be positioned at any<br/>particular location on the housing which is known in the art. In<br/>addition, while discs 12 are shown herein as being relatively thin, flat<br/>members with a small gap 56 between the outer edge of the disc and<br/>the inner surface of ring 18, it will be appreciated that they may be of<br/>any particular design known in the art. For example, they may be<br/>curved as disclosed in Effenberger and/or the distance between<br/>adjacent discs may vary radially outwardly from shaft 20. Further, the<br/>perimeter of discs 12 need not be circular but may be of any other<br/>particular shape. Accordingly, discs 12 have also been referred to<br/>herein as "spaced apart members".<br/> Referring to Figures 3 and 4a-d, preferred embodiments<br/>for spaced apart members 12 are shown. As shown in Figure 3, spaced<br/>apart members 12 have an inner edge 40 and an outer edge 42. If spaced<br/>apart member 12 has a central circular opening 22, then inner edge 40<br/>defines the inner diameter of spaced apart member 12. Further, if the<br/>periphery of spaced apart member 12 is circular, then outer edge 42<br/>defines the outer diameter of spaced apart member 12.<br/> Spaced apart members 12 may extend at any angle form<br/>shaft 20 as is known in the art and preferably extend at a right angle<br/>from shaft 20. Further, spaced apart member 12 may have any<br/><br/> CA 02258419 1999-O1-08<br/>-10-<br/>curvature known in the art and may be curved in the upstream or<br/>downstream direction (as defined by the fluid flow through housing<br/>14). Preferably, spaced apart member 12 is planer so as to extend<br/>transversely outwardly from shaft 20. In this specification, all such<br/>spaced apart members are referred to as extending transversely<br/>outwardly from longitudinally extending shaft 20.<br/>Each spaced apart member 12 has two opposed sides 44 and<br/>46 which extend transversely outwardly from inner edge 40 to outer<br/>edge 42. These surfaces define the motive force transfer region 26 of<br/>spaced apart members 12. The spacing between adjacent spaced apart<br/>members 12 may be the same or may vary as is known in the art.<br/> Without being limited by theory, as a fluid travels across<br/>motive force transfer region 26, the difference in rotational speed<br/>between the fluid and spaced apart member 12 causes a boundary layer<br/>of fluid to form adjacent opposed surfaces 44, 46. If the fluid is<br/>introduced through openings 22, then the fluid will rotate in a spiral<br/>fashion from inner edge 40 outwardly towards outer edge 42. At some<br/>intermediate point, the fluid will have sufficient momentum that it<br/>will separate from opposed surfaces 44, 46 (i.e. it will delaminate) and<br/>travel towards the fluid exit port. By thickening the boundary layer, for<br/>a given rotation of a spaced apart member 12, additional motive force<br/>may be transferred between the rotating spaced apart member 12 and<br/>the fluid. Thus the efficiency of the motive force transfer between<br/>spaced apart members 12 and the fluid may be increased.<br/> The boundary layer may be thickened for a particular<br/>opposed surface 44, 46 of a particular spaced apart member by<br/>providing an area on that spaced apart member 12 having an increased<br/>width (i.e. in the longitudinal direction) at at least one discrete location<br/>of the particular opposed surface 44, 46. Preferably, a plurality of such<br/>areas of increased width are provided on each opposed surface 44, 46 of<br/>a particular spaced apart member 12. Further, preferably such areas of<br/><br/> CA 02258419 1999-O1-08<br/>-11-<br/>increased width are provided on at least some, preferably a majority<br/>and most preferably all of spaced apart members of turbine 10.<br/> Referring to Figures 3 and 4, the discrete areas of increased<br/>width may be provided by having raised portions 48 which are<br/>positioned at any place on surface 44, 46. As shown in Figure 3, these<br/>may be positioned on the inner portion of spaced apart member 12<br/>such as adjacent inner edge 40 or spaced some distance outwardly from<br/>inner edge 40. Raised portion 48 preferably is positioned on the inner<br/>portion of spaced apart member 12. Further, a series of raised portions<br/>48 may be sequentially positioned outwardly on spaced apart member<br/>12 so as to successively thicken the boundary layer as it encounters a<br/>plurality of raised areas 48.<br/> Raised portion 48 is a discontinuity or increased width in<br/>surface 44, 46 which the fluid encounters as it rotates around spaced<br/>apart member 12. As the fluid passes over raised portion 48, the<br/>boundary layer thickens. By passing the fluid over a series of raised<br/>portions, the boundary layer may be continuously thickened. This is<br/>advantageous as the thicker the boundary layer, the more energy is<br/>transferred between the rotating spaced apart members and the fluid.<br/> Side 50 of raised portion 48 may extend generally<br/>perpendicular to surface 44, 46 (eg. raised portion 48 may be a generally<br/>square or rectangular protuberance as shown in Figure 4b) at an obtuse<br/>angle alpha (eg. 102 - 122°) to surface 44, 46 (eg. raised portion 48 <br/>may be<br/>a generally triangular protuberance as shown in Figure 4c), or a<br/>rounded member on surface 44, 46 (eg. raised portion 48 may be a<br/>generally hemispherical protuberance as shown in Figure 4c). Raised<br/>portion 48 may be constructed as a point member so as to be positioned<br/>at a discrete location on surface 44, 46. Alternately, it may extend for an<br/>indefinite length as shown in Figure 3.<br/> Side 50 is preferably positioned such that the direction of<br/>travel of the fluid as it encounters side 50 is normal to side 50. As the<br/><br/> CA 02258419 1999-O1-08<br/>-12-<br/>travels outwardly over surface 44, 46, it will be subjected to both<br/>tangential and radial acceleration as shown by arrows T and R in figure<br/>3. Generally, these forces will cause the fluid to travel outwardly at an<br/>angle of about 40° to the radial as shown in Figure 3. By positioning<br/>side 50 at such an angle (eg. 30° to 50°), the direction of <br/>travel of the<br/>fluid as it encounters side 50 will be about 90°.<br/> Raised portion 48 may have a vertical height from surface<br/>44, 46 varying from about 0.5 to about 25, preferably from about 0.5 to<br/>about 10 and more preferably 0.5 to about 2 of the thickness of the<br/>boundary layer immediately upstream of raised portion 48.<br/> The boundary layer may be delaminated from a particular<br/>opposed surface 44, 46 of a particular spaced apart member 12, or the<br/>delamination of the boundary layer from a particular opposed surface<br/>44, 46 of a particular spaced apart member 12, may be assisted by<br/>providing an area on that spaced apart member 12 having an increased<br/>width (i.e. in the longitudinal direction) at at least one discrete location<br/>of the particular opposed surface 44, 46. Preferably, a plurality of such<br/>areas of increased width are provided on each opposed surface 44, 46 of<br/>a particular spaced apart member 12. Further, preferably such areas of<br/>increased width are provided on at least some, preferably a majority<br/>and most preferably all of spaced apart members of turbine 10.<br/> Referring to Figures 3 and 4a-4d, such discrete areas of<br/>increased width may be provided by having raised portions 52 which<br/>are positioned on surface 44, 46. As shown in Figure 3, these may be<br/>positioned on the outer portion of spaced apart member 12 such as<br/>adjacent outer edge 42 or spaced some distance inwardly from outer<br/>edge 42.<br/> As the fluid travels over opposed surface 44, 46, it<br/>encounters raised portion 52. This results in, or assists in, the<br/>delamination of the boundary layer from opposed surface 44, 46. If the<br/>fluid has not delaminated from opposed surface 44, 46 when it reaches<br/><br/> CA 02258419 1999-O1-08<br/>-13-<br/>outer edge 42 then the delamination process will absorb energy from<br/>the prandtl layer turbine thereby reducing the overall efficiency of the<br/>prandtl layer turbine.<br/> Raised portions 52 may be positioned adjacent outer edge<br/>42 or at an intermediate position inwardly thereof as shown in Figure<br/>3. Further, as with raised portion 48, raised portion 52 preferably has an<br/>upstream side 54 which is a marked discontinuity to opposed surface<br/>44, 46. As shown in Figure 4a, side 54 extends longitudinally outwardly<br/>from surface 44, 46. However, raised portions 52 may have the same<br/>shape as raised portions 48.<br/> As fluid travels radially outwardly between inner edge 40<br/>and outer edge 42, a boundary layer is produced (with or without<br/>raised portions 48) which thickens as the boundary layer moves<br/>radially outwardly from shaft 20. Preferably, at least one raised portion<br/>54 is positioned radially outwardly on opposed surface 44, 46.<br/> Preferably, raised portion 52 may be positioned at any point on surface<br/>44, 46 where it is desired to commence the delamination process.<br/> Typically, the fluid will commence to delaminate at a position where<br/>the fluid has a velocity of about 103 to about 105 mach. Accordingly,<br/>raised portion 52 is positioned adjacent such a position and preferably<br/>just upstream of where the fluid reaches about 103 mach. This velocity<br/>corresponds to the region where the boundary layer achieves fluid<br/>flow characteristics which but for raised portion 52 would cause the<br/>fluid to delaminate.<br/> Raised portion 52 may have a vertical height from surface<br/>44, 46 varying from about 1 to about 100, preferably from about 1 to<br/>about 25 and more preferably 1 to about 5 of the thickness of the<br/>boundary layer immediately upstream of raised portion 52.<br/> In another embodiment, any of the spaced apart members<br/>12 may include both one or more raised areas 48 to assist in thickening<br/>the boundary layer and one or more raised areas 52 to assist in the<br/><br/> CA 02258419 1999-O1-08<br/>-14-<br/>delamination of the boundary layer.<br/> In the specification, the word "fluid" is used to refer to<br/>both liquids and gases. In addition, due to the formation of a boundary<br/>layer adjacent opposed surfaces 44, 46, the fluid may include solid<br/>material since the formation of the boundary layer results in a<br/>reduction of, or the prevention of, damage to the surface of spaced<br/>apart members 12 by abrasion or other mechanical action of the solid<br/>material. For this reason, spaced apart members 12 may be made from<br/>any materials known in the art including plastic, metal, such as<br/>stainless steel, composite material such as KevlarTM and reinforced<br/>composite materials such as carbon fibre or metal mesh reinforced<br/> KevlarTM.<br/> In a further preferred embodiment of the instant<br/>invention, one or more fan members 68, 70 may be provided to assist<br/>in the movement of air through the prandtl layer turbines (see for<br/>example Figure 5). This figure also shows a further alternate<br/>embodiment in which two prandtl layer turbines units 64, 66, each of<br/>which comprises a plurality of discs 12, are provided in a single<br/>housing 14. Each prandtl layer turbine unit 64, 66 is provided with an<br/>inlet 60 having a single outlet 62. Discs 12 of each prandtl layer turbine<br/>64, 66 are mounted on a common shaft 20. This particular<br/>embodiment may advantageously be used to reduce the pressure drop<br/>through the prandtl layer turbine. For example, instead of directing all<br/>of the fluid at a set number of spaced apart members 12, half of the<br/>fluid may be directed to one half of the spaced apart members (prandtl<br/>layer turbine unit 64) and the other half may be directed at another set<br/>of spaced apart members (prandtl layer turbine unit 66). Thus the<br/>mean path through the prandtl layer turbine is reduced by half<br/>resulting in a decrease in the pressure loss as the fluid passes through<br/>prandtl layer turbine 10. In the embodiment of Figure 5, the fluid feed<br/>is split in two upstream of housing 14 (not shown). Alternately, as<br/><br/> CA 02258419 1999-O1-08<br/>-15-<br/>shown in Figures 10 and 11, all of the fluid may be fed to a single inlet<br/>60 which is positioned between prandtl layer turbine units 64, 66.<br/> While in these embodiments a like number of similar spaced apart<br/>members 12 have been included in each prandtl layer turbine unit 64,<br/>66, each turbine unit 64, 66 may incorporate differing number of spaced<br/>apart members 12 and/or differently configured spaced apart members<br/>12.<br/> It will be appreciated that discs 12 of prandtl layer turbine<br/>unit 64 may be mounted on a first shaft 20 and discs 12 of the second<br/>prandtl layer turbine unit 66 may be mounted on a separate shaft 20<br/>(not shown). This alternate embodiment may be used if the two shaft<br/>are to be rotated at different speeds. This can be advantageous if the<br/>prandtl layer turbine is to be used to as a separator as discussed below.<br/> If spaced apart members 12 are of the same design, then the different<br/>rotational speed of spaced apart members 12 will impart different flow<br/>characteristics to the fluid and this may beneficially be used to separate<br/>the fluid (or particles entrained into the fluid) into different fluid<br/>streams, each of which has a different composition.<br/> Fan member 68 may be of any particular construction that<br/>will transport, or will assist in transporting, fluid to opening 22 of<br/>spaced apart member 12. Similarly, fan member 70 may be of any<br/>particular construction that will assist in the movement of fluid<br/>through unit 64, 66 and transport it, or assist in transporting it, to an<br/>outlet 62. Fan member 68 acts to pressurize the fluid and to push it<br/>downstream to one or more of spaced apart members 12. Conversely,<br/>fan member 70 acts to create a low pressure area to pull the fluid<br/>downstream, either through downstream spaced apart members 12 or<br/>through outlet 62. Fan member 70 may optionally be positioned<br/>outside of the interior of ring 18 so as to draw the fluid from housing<br/>14. Such a fan member may be of any particular construction.<br/> As shown by Figure 5, a fan member 68 may be positioned<br/><br/> CA 02258419 1999-O1-08<br/>-16-<br/>immediately upstream of the first spaced apart member 12 of prandtl<br/>layer turbine unit 64. It will also be appreciated as also shown in Figure<br/>that fan member 68 may be positioned upstream from upstream end<br/>78 of prandtl layer combining at 66. Fan member 68 has a plurality of<br/>5 blades 72 which are configured to direct fluid towards central opening<br/>22 of the first spaced apart member 12. Blades may be mounted on a<br/>hub so as to rotate around shaft 20. Alternately, for example, fan 70<br/>may be a squirrel cage fan or the like. As shown in Figure 5, blades 72<br/>are angled such that when fan member 68 rotates, fluid is directed<br/>under pressure at central opening 22.<br/> Fan member 68 may be non-rotationally mounted on<br/>shaft 20 so as to rotate with spaced apart members 12. Alternately, fan<br/>member 68 may be mounted for rotation independent of the rotation<br/>of shaft 20, such as by bearings 76 which engage ring 18 (as shown in<br/>dotted outline in Figure 5) or fan member 68 may be driven by a motor<br/>if it is mounted on a different shaft (not shown). If the prandtl layer<br/>turbine is functioning as a pump, then if fan member 68 is non-<br/>rotationally mounted on shaft 20, the rotation of shaft 20 will cause<br/>blades 72 to pressurize the fluid as it is introduced into the rotating<br/>spaced apart members. Alternately, if the prandtl layer turbine unit is<br/>to function as a motor, the movement of the fluid through housing 14<br/>may be used to cause spaced apart members 12 to rotate and,<br/>accordingly, fan member 68 to rotate (if fan member 68 is freely<br/>rotatably mounted in housing 14). By pressurizing the fluid as it<br/>enters the spaced apart members with no other changes to spaced apart<br/>members 12, the pressure at outlet 62 is increased. As the downstream<br/>pressure may be increased, then there is additional draw on the fluid<br/>which allows additional spaced apart members 12 to be added to the<br/>prandtl layer turbine unit 64, 66.<br/> Outlet fan members 70 may be mounted in the same<br/>manner as fan member 68. For example, outlet fan 70 may be non-<br/><br/> CA 02258419 1999-O1-08<br/>-17-<br/>rotatably mounted on shaft 20, or rotatably mounted in housing 14<br/>independent of spaced apart member 12 such as by a bearing 76 (not<br/>shown). Blade 72 may be configured so as to direct fluid out of<br/>housing 14 through outlet 62. If fan member 70 is outside housing 14,<br/>then fan member is constructed so as to draw fluid from outlet 62 (not<br/>shown). By providing a source of decreased pressure at or adjacent<br/>outlet 62, additional spaced apart members may be provided in a single<br/>prandtl layer turbine unit 64, 66. Further, an increased amount of the<br/>fluid may travel towards downstream end 80 such that the amount of<br/>fluid which passes over each spaced apart member 12 will be more<br/>evenly distributed.<br/> In another preferred embodiment of the instant<br/>invention, the surface area of motive force transfer region 26 of<br/>opposed surfaces 44, 46 varies between at least two immediately<br/>adjacent spaced apart members 12. This may be achieved by varying<br/>one or both of the inner diameter and the outer diameter of spaced<br/>apart members 12.<br/> Preferably, for at least a portion of the spaced apart<br/>members 12 of a prandtl layer turbine unit 64, 66, the distance between<br/>inner edge 40 and outer edge 42 of a spaced apart member 12 varies to<br/>that of a neighbouring spaced apart member 12. More preferably, the<br/>distance between inner edge 40 and outer edge 42 of a spaced apart<br/>member 12 varies to that of a neighbouring spaced apart member 12<br/>for all spaced apart members in a prandtl layer turbine unit 64, 66. The<br/>distance between inner edge 40 and outer edge of 42 of spaced apart<br/>members 12 may increase in the downstream direction and preferably<br/>increases from upstream end 78 towards downstream end 80.<br/> Alternately, the distance between inner edge 40 and outer edge of 42 of<br/>spaced apart members 12 may decrease in the downstream direction<br/>and preferably decreases from upstream end 78 towards downstream<br/>end 80.<br/><br/> CA 02258419 1999-O1-08<br/>-18-<br/> As shown in Figures 5 and 6, the size of central opening 22<br/>of at least one of the discs of prandtl air turbine unit 64, 66 varies from<br/>the size of the central opening of the remaining spaced apart members<br/>12 of that prandtl air turbine unit.<br/> Figure 6 is a schematic diagram, in flow order, of the top<br/>plan views of spaced apart members 12 of prandtl layer turbine unit 64.<br/> As shown in this drawing, each spaced apart member has a centrally<br/>positioned shaft opening 74 for non-rotatably receiving shaft 20 (if<br/>shaft 20 has a square cross-section similar in size to that of shaft<br/>opening 74). It will be appreciated that spaced apart members 12 may be<br/>fixedly mounted to shaft 20 by any means known in the art.<br/> In a more preferred embodiment, a major proportion of<br/>the spaced apart members have central openings 22 which are of<br/>varying sizes and, in a particularly preferred embodiment, the size of<br/>cental opening 22 varies amongst all of the spaced apart members of a<br/>prandtl layer turbine unit 64, 66. An example of this construction is<br/>also shown in Figures 8 and 9.<br/> As the size of central opening 22 increases, then the<br/>amount of fluid which may pass downstream through the cental<br/>opening 22 of a spaced apart member 12 increases. Accordingly, more<br/>fluid may be passed downstream to other spaced apart members where<br/>the fluid may be accelerated. The size of central opening 22 may<br/>decrease in size for at least a portion of the spaced apart members 12<br/>between upstream end 78 and downstream end 80. As shown in the<br/>embodiment of Figure 8, the size of central opening 22 may<br/>continually decrease in size from upstream end 78 to downstream end<br/>80.<br/> An advantage of this embodiment is that the amount of<br/>fluid which may pass through housing 14 per unit of time is increased.<br/> This is graphically represented in Figure 7 wherein the relative<br/>amount of fluid which may flow per unit time through a prandtl layer<br/><br/> CA 02258419 1999-O1-08<br/>-19-<br/>turbine may be maximized by adjusting the ratio of the inner diameter<br/>of a spaced apart member 12 to its outer diameter. This ratio will vary<br/>from one prandtl layer turbine to another depending upon, inter alia,<br/>the speed of rotation of spaced apart members 12 when the turbine is<br/>in use, the spacing between adjacent spaced apart members. However,<br/>as the size of cental opening 22 increases, then, for a given size of a<br/>spaced apart member 12, the surface area of motive force transfer<br/>region 26 of spaced apart member 12 is decreased. Accordingly, this<br/>limits the velocity which the fluid may achieve as it travels between<br/>inner edge 40 and outer edge 42 of a spaced apart member 12 on its way<br/>to outlet 62. Thus, by increasing the amount of fluid which may flow<br/>through the prandtl layer turbine 10, the amount of suction which<br/>may be exerted on the fluid at inlet 60 is decreased as is also shown in<br/> Figure 7.<br/> The size of central opening 22 may increase in size for at<br/>least a portion of the spaced apart members 12 between upstream end<br/>78 and downstream end 80. As shown in Figure 9, the size of cental<br/>opening 22 may continuously increase from upstream end 78 to<br/>downstream end 80. Less fluid passes through each central opening 22<br/>to the next spaced apart member 12 in the downstream direction.<br/> Accordingly, less fluid will be available to be accelerated by each<br/>successive spaced apart member 12 and accordingly each successive<br/>spaced apart member 12 may have a smaller motive force transfer area<br/>26 to achieve the same acceleration of the fluid adjacent the opposed<br/>surface 44, 46 of the respective spaced apart member 12.<br/> In the embodiments of Figures 8 and 9, the size of<br/>openings 22 varies from one spaced apart member to the next so as to<br/>form, in total, a generally trumpet shaped path (either decreasing from<br/>upstream end 78 to downstream end 80 (Figure 8) or increasing from<br/>upstream end 78 to downstream end 80 (Figure 9). It will be<br/>appreciated that the amount of difference between the size of central<br/><br/> CA 02258419 1999-O1-08<br/>-20-<br/>openings 22 of any to adjacent spaced apart members 12 may vary by<br/>any desired amount. Further, the size of the openings may alternately<br/>increase and decrease from one end 78, 80 to the other end 78, 80.<br/> As shown in Figure 5, more than one prandtl layer<br/>turbine unit 64, 66 may be provided in a housing 14. Further, the size<br/>of central opening 22 of the spaced apart members 12 of any particular<br/>prandtl layer turbine unit 64, 66 may vary independent of the change<br/>of size of central openings 22 of the spaced apart members 12 of a<br/>different prandtl layer turbine 64, 66 in the same housing 14 (not<br/>shown). As shown in Figure 5, the size of central opening 22 decreases<br/>from each upstream end 78 to each downstream end 80. However, it<br/>will be appreciated that, if desired, for example, the size of central<br/>openings 22 may decrease in size from upstream end 78 to<br/>downstream end 80 of prandtl air turbine unit 64 while the size of<br/>central openings 22 may increase in size from upstream end 78 to<br/>downstream end 80 of prandtl layer turbine unit 66.<br/> Figures 10 and 11 show a further alternate embodiment<br/>wherein the size of cental openings 22 varies from end 78, 80 to the<br/>other end 78,80. In this particular design, the fluid inlet is positioned<br/>centrally between two prandtl layer turbine units 64, 66. In the<br/>embodiment of Figure 10, the size of cental opening 22 increases from<br/>upstream end 78 to downstream end 80 thus producing a prandtl layer<br/>turbine 10 which has improved suction. This is particularly useful if<br/>the prandtl layer turbine is to be used as a pump or fan to move a<br/>fluid.<br/> In the embodiment of Figure 11, the size of central<br/>opening 22 decreases from upstream end 78 to downstream end 80<br/>thus producing a prandtl layer turbine 10 that has improved fluid<br/>flow. This particular embodiment would be advantageous if the<br/>prandtl layer turbine end were used as a compressor or pump.<br/> In the embodiments of Figure 5 - 9, each spaced apart<br/><br/> CA 02258419 1999-O1-08<br/>-21-<br/>member 12 is in the shape of a disc which has the same outer<br/>diameter. Further, the housing has a uniform diameter. Accordingly,<br/>for each spaced apart member 12, space 56 (which extends from outer<br/>edge 42 of each spaced apart member 12 to the inner surface of<br/>longitudinally extending 18) has the same radial length. In a further<br/>alternate embodiment of this invention, the outer diameter of each<br/>spaced apart member 12 may vary from one end 78, 80 to the other end<br/>78, 80 (see Figures 12 and 13). In such an embodiment, space 56 may<br/>have a differing radial length (see Figure 12) or it may have the same<br/>radial length (see Figure 13). If prandtl layer turbine 10 is to be used as a<br/>separator, the then space 56 preferably includes a portion 56a which is<br/>an area of reduced velocity fluid (eg. a dead air space) in which the<br/>separated material may settle out without being re-entrained in the<br/>fluid. For example, as shown in Figure 12b, ring 18 has an elliptical<br/>portion so as to provide portion 56a.<br/> It will be appreciated that in either of these embodiments,<br/>the size of cental opening 22 may remain the same (as is shown in<br/> Figure 13) or, alternately, cental opening 22 may vary in size. For<br/>example, as shown in Figure 12, cental opening may increase in size<br/>from upstream end 78 to downstream end 80. This particular<br/>embodiment is advantageous as it increases the negative pressure in<br/>housing 14 at downstream end 80. and increases the fluid flow<br/>through prandtl layer turbine 10. Alternately, the size of cental<br/>opening 22 may vary in any other manner, such as by decreasing in<br/>size from upstream end 78 to downstream end 80 (not shown).<br/> In a further preferred embodiment of the instant<br/>invention, a plurality of prandtl layer turbine units 64, 66 may be<br/>provided wherein the surface area of the motive force transfer region<br/>26 of the spaced apart members 12 of one prandtl layer turbine unit 64,<br/>66 have is different to that of the spaced apart members 12 of another<br/>prandtl layer turbine unit 64, 66. This may be achieved by the outer<br/><br/> CA 02258419 1999-O1-08<br/>-22-<br/>diameter of at least some of the spaced apart members 12 of a first<br/>prandtl layer turbine unit 64 having an outer diameter which is<br/>smaller than the outer diameter of at least some of the spaced apart<br/>members 12 of a second prandtl layer turbine unit 66. In a preferred<br/>embodiment, all of the spaced apart members 12 of prandtl layer<br/>turbine unit 64 have an outer diameter which is smaller than the<br/>outer diameter of each of the spaced apart members 12 of prandtl layer<br/>turbine unit 66. Examples of these embodiments are shown in Figures<br/>14 - 17. It will be appreciated that more than two prandtl layer turbine<br/>units 64, 66 may be provided in any particular prandtl layer turbine 10.<br/> Two have been shown in Figures 14 - 17 for simplicity of the drawings.<br/> Referring to Figures 14 and 15, the spaced apart members<br/>12 of prandtl layer turbine unit 64 have the same outer diameter and<br/>the spaced apart members 12 of prandtl layer turbine unit 66 have the<br/>same outer diameter. The outer diameter of the spaced apart members<br/>12 of prandtl layer turbine unit 64 is smaller than the outer diameter of<br/>the spaced apart members 12 of prandtl layer turbine unit 66. As<br/>discussed above with respect to Figures 5 - 13, the outer diameter<br/>and/or the inner diameter of the spaced apart members of one or both<br/>of prandtl layer turbine units 64, 66 may vary so that the surface area of<br/>motive force transfer area 26 may vary from one spaced apart member<br/>12 to another spaced apart member 12 in one or both of prandtl layer<br/>turbine units 64, 66.<br/> As shown in Figure 14, prandtl layer turbine unit 64 is<br/>provided in series with prandtl layer turbine unit 66. Further, the<br/>spaced apart members 12 of prandtl layer turbine unit 64 are non-<br/>rotatably mounted on shaft 20' and the spaced apart members 12 of<br/>prandtl layer turbine unit 66 are non-rotatably mounted on shaft 20. It<br/>will be appreciated that prandtl layer turbine unit 64 may be provided<br/>in the same housing 14 as prandtl layer turbine unit 66 or, alternately,<br/>it may be provided in a separate housing which is an airflow<br/><br/> CA 02258419 1999-O1-08<br/>-23-<br/>communication with the housing of prandtl layer turbine unit 66.<br/> Preferably, in such an embodiment, each prandtl layer turbine unit 64,<br/>66 is mounted co-axially. Optionally, the spaced apart members of<br/>prandtl layer turbine units 64 and 66 may be non rotationally mounted<br/>on the same shaft 20 (see for example Figures 16 and 17).<br/> Prandtl layer turbine unit 64 has inlet 60' and is<br/>rotationally mounted on shaft 20' whereas prandtl layer turbine unit<br/>66 as an inlet 60 and is mounted for rotation on shaft 20. Fluid passes<br/>through spaced apart members 12' to outlet 62' from where it is fed to<br/>inlet 60 such as via passage 61. Thus the fluid introduced into prandtl<br/>layer turbine unit 66 may have an increased pressure. Passage 61 may<br/>extend in a spiral to introduce fluid tangentially to prandtl layer<br/>turbine units 66. Thus the fluid introduced into prandtl layer turbine<br/>unit 66 may already have rotational momentum in the direction of<br/>rotation of spaced apart members 12.<br/> In a further preferred embodiment as shown in Figures 16<br/>and 17, prandtl layer turbine unit 64 may be nested within prandtl<br/>layer turbine unit 66. For ease of reference, in Figure 16, the cental<br/>openings and motive force transfer regions of prandtl layer turbine<br/>unit 64 are denoted by reference numerals 22' and 26'. The central<br/>opening and motive force transfer regions of the spaced apart<br/>members of prandtl layer turbine unit 66 are denoted by reference<br/>numerals 22 and 26. The spaced apart members of prandtl layer turbine<br/>units 64 and 66 may be mounted on the same shaft 20 or the spaced<br/>apart members of each prandtl layer turbine unit 64, 66 may be<br/>mounted on its own shaft 20 (as shown in Figure 14).<br/> It will be appreciated that prandtl layer turbine unit 64<br/>may be only partially nested within prandtl layer turbine 66. For<br/>example, the upstream spaced apart members 12 of prandtl layer<br/>turbine unit 64 may be positioned upstream from the first spaced apart<br/>member 12 of prandtl layer turbine unit 66 (not shown). Further,<br/><br/> CA 02258419 1999-O1-08<br/>-24-<br/>prandtl layer turbine units 64, 66 need not have the same length. For<br/>example, as shown in Figure 16, prandtl layer turbine unit 64<br/>comprises four discs whereas prandtl layer turbine unit 66 comprises<br/>seven discs. In this embodiment, the prandtl layer turbine unit 64<br/>commences at the same upstream position as prandtl layer turbine<br/>unit 66 but terminates at a position intermediate of prandtl layer<br/>turbine unit 66. It will be appreciated that prandtl layer turbine unit 64<br/>may extend conterminously for the same length as prandtl layer<br/>turbine unit 66. Further, it may commence at a position downstream<br/>of the upstream end of prandtl layer turbine unit 66 and continue to<br/>an intermediate position of prandtl layer turbine unit 66 or it may<br/>terminate to or past the downstream end of prandtl layer turbine unit<br/>66.<br/> In a further alternate preferred embodiment, as shown in<br/> Figure 14, prandtl layer turbine unit 64 is rotationally mounted on<br/>shaft 20' whereas prandtl layer turbine unit 66 is mounted for rotation<br/>on shaft 20. For example, shaft 20' may be rotationally mounted<br/>around shaft 20 by means of bearings 82 or other means known in the<br/>art. In this manner, spaced apart members 12 of prandtl layer turbine<br/>unit 64 may rotate at a different speed to spaced apart members 12 of<br/>prandtl layer turbine unit 66. Preferably, prandtl layer turbine unit 64<br/>(which has spaced apart members 12 having a smaller outer diameter)<br/>rotates at a faster speed than prandtl layer turbine unit 66. For<br/>example, if a first prandtl layer turbine unit had discs having a two<br/>inch outer diameter, the prandtl layer turbine unit could rotate at<br/>speeds up to, eg., about 100,000 rpm. A second prandtl layer turbine<br/>unit having larger sized discs (eg. discs having an outer diameter from<br/>about 3 to 6 inches) could rotate at a slower speed (eg. about 35,000<br/>rpm). Similarly, a third prandtl layer turbine unit which had discs<br/>having an even larger outer diameter (eg. from about 8 to about 12<br/>inches) could rotate at an even slower speed (eg. about 20,000 rpm). In<br/><br/> CA 02258419 1999-O1-08<br/>-25-<br/>this way, the smaller discs could be used to pressurize the fluid which<br/>is subsequently introduced into a prandtl layer turbine unit having<br/>larger discs. By boosting the pressure of the fluid as it is introduced to<br/>the larger, slower rotating discs, the overall efficiency of the prandtl<br/>layer turbine 10 may be substantially increased. In particular, each stage<br/>may be designed to operate at its optimal flow or pressure range.<br/> Further, if the fluid is compressible. For example, the increase in the<br/>inlet pressure will increase the outlet pressure, and therefore the<br/>pressure throughout housing 14. This increase in pressure, if<br/>sufficient, will compress the fluid (eg. a gas or a compressible fluid) in<br/>housing 14. This increases the density of the fluid and the efficiency of<br/>the transfer of motive force between the fluid and the spaced apart<br/>members.<br/> Referring to Figures 18 and 19, a further preferred<br/>embodiment of the instant invention is shown. Fluid outlet port 62<br/>extends between a first end 84 and a second end 86. Traditionally, in<br/>prandtl layer turbine units, outlet port 62 has extended along a straight<br/>line between first and second ends 84 and 86. According to the<br/>preferred embodiment shown in Figures 18 and 19, second and 86 of<br/>fluid outlet port 62 is radially displaced around housing 14 from first<br/>end 84. The portion of the fluid that passes downstream through<br/>opening 22 of a spaced apart member 12 will have some rotational<br/>momentum imparted to in even though it does not pass outwardly at<br/>that location adjacent that spaced apart member. Therefore, assuming<br/>that all spaced apart members are similar, the portion of the fluid<br/>which passes outwardly along the next spaced apart member will<br/>delaminate at a different position due to the rotational momentum<br/>imparted by its passage through opening 22 in the immediate<br/>upstream spaced apart member. Outlet 62 is preferably configure to<br/>have an opening in line with the direction of travel of the fluid as it<br/>delaminates and travels to ring 18. Thus downstream portions of<br/><br/> CA 02258419 1999-O1-08<br/>-26-<br/>outlet 62 are preferably radially displaced along ring 18 in the direction<br/>of rotation of spaced apart members 12.<br/> Preferably, fluid outlet port 62 is curved and it may extend<br/>as a spiral along ring 18. Preferably, the curvature or spiral extends in<br/>the same direction as the rotation of the spaced apart members 12. The<br/>fluid flow in prandtl layer turbine 10 is generally represented by the<br/>arrow shown in Figure 19. As represented by this arrow, the fluid will<br/>travel in a spiral path outwardly across an opposed surface 44, 46 and<br/>then radially outwardly through fluid outlet port 62. Fluid outlet port<br/>62 preferably curves in the same direction as the direction of the<br/>rotation of the spaced apart members.<br/> It will be appreciated that all of fluid outlet port 62 need<br/>not be curved as shown in Figures 18 and 19. For example, a portion of<br/>fluid outlet port 62 may be curved and the remainder may extend in a<br/>straight line as is known in the prior art. It will further be appreciated<br/>that while fluid outlet port 62 in Figure 18 extends conterminously<br/>with spaced apart members 12, first and second ends 84 and 86 need<br/>not coincide with the upstream and downstream ends of the spaced<br/>apart members 12. In particular, fluid outlet port 62 may have any<br/>longitudinal length as is known in the art.<br/> According to further preferred embodiment of the instant<br/>invention, a single prandtl layer turbine unit 64, 66 may have a<br/>plurality of outlets 62. Each outlet 62 may be constructed in anv<br/>manner known in the art or, alternately they may be constructed as<br/>disclosed herein. For example, they may extend in a spiral or curved<br/>fashion around ring 18 in the direction of rotation of spaced apart<br/>members 12 of a prandtl layer turbine unit 64, 66. Referring to Figure<br/>20, the ring of a prandtl layer turbine 10 having a single prandtl layer<br/>turbine unit 64, 66 is shown. In this embodiment, two outlets, 90 and<br/>92 are provided. Each outlet extends longitudinally along ring 18 from<br/>upstream end 78 of spaced apart members 12 to downstream end 80 of<br/><br/> CA 02258419 1999-O1-08<br/>-27-<br/>spaced apart members 12. For ease of reference, spaced apart members<br/>12 have not been shown in Figure 20.<br/> Each outlet 90, 92 may be of any particular construction<br/>known in the art or taught herein. For example, each outlet 90, 92 may<br/>extend in a curve or spiral around ring 18. Outlets 90, 92 may have the<br/>same degree of curvature or, alternately, the degree of curvature may<br/>vary to allow separation of a specific density and mass of particulate<br/>matter. For example, if prandtl layer turbine 10 is used for particle<br/>separation, particles having a different shape and/or mass will travel<br/>outwardly at different positions. The outlets are preferably positioned<br/>to receive such streams and thus their actual configuration will vary<br/>depending upon the particle separation characteristics of the turbine.<br/> Each outlet 90, 92 may curve in the same direction (eg. the<br/>direction of rotation of spaced apart members 12). Alternately, they<br/>may curve in opposite directions or one or both may extend in a<br/>straight line as is known in the prior art. Further, a plurality of such<br/>outlets 90 may be provided.<br/> It will be appreciated that in an alternate embodiment,<br/>each outlet 90, 92 may be a portion 56a wherein the separated<br/>particulate matter may settle out and be removed from housing 14 and<br/>an outlet 62 may be provided to receive the fluid from which the<br/>particulate material has been removed.<br/> Assuming that the portion of a fluid which is introduced<br/>through a central opening 22 to a position adjacent an opposed surface<br/>44, 46 has approximately the same momentum, and assuming that the<br/>fluid has portions of differing density, then the rotation of spaced apart<br/>member 12 will cause the portions of the fluid having differing<br/>densities to commence rotating around shaft 20 at differing rates. As<br/>the fluid travels outwardly between inner edge 40 and outer edge 42<br/>during its travel around shaft 20, the portions of the fluid having<br/>differing densities will tend to delaminate and travel outwardly<br/><br/> CA 02258419 1999-O1-08<br/>-28-<br/>towards ring 18 at different locations around ring 18. Accordingly, in a<br/>preferred embodiment of this invention, a fluid outlet port is<br/>positioned to receive each portion of the fluid as it delaminates from<br/>the opposed surface. Accordingly, in the embodiment shown in<br/> Figure 20, it is assumed that the fluid would contain two distinctive<br/>portions (eg. two elements having differing densities). Fluid outlet<br/>ports 90 and 92 are angularly displaced around ring 18 so as to each<br/>receive one of these portions.<br/> If the fluid also contains a solid, then, due to aerodynamic<br/>effects, particles having the same density but differing sizes will tend to<br/>separate due to the centrifugal forces exerted upon the particles as they<br/>travel in the fluid from inner edge 40 to outer edge 42. Accordingly, a<br/>prandtl layer turbine may also be utilized as a particle separator. For<br/>example, in the embodiment of Figure 20, if the particles have the<br/>same density, then first outlet 90 may be positioned to receive particles<br/>having a first particle sized distribution and fluid outlet port 92 may be<br/>positioned to receive particles having a smaller particle size<br/>distribution.<br/> The positioning of fluid outlet ports 90, 92 may be selected<br/>based upon several factors including the total mass and density of the<br/>fluid and/or particles to be separated, the amount of centrifugal force<br/>which is imparted to the fluid and any entrained particles by spaced<br/>apart members 12 (eg. the inner diameter of spaced apart members 12,<br/>the outer diameter spaced apart members 12, the longitudinal spacing<br/>between adjacent spaced apart members 12, the disc thickness and the<br/>speed of rotation of spaced apart members 12).<br/> In the embodiment of Figure 20, outlets 90 and 92 may be<br/>in flow communication with any downstream apparatus which may<br/>be desired. Accordingly, each portion of the fluid may be passed<br/>downstream for different processing steps.<br/> Referring to Figure 21, two cyclones 94, 96 may be<br/><br/> CA 02258419 1999-O1-08<br/>-29-<br/>provided in flow communication with fluid outlet ports 90, 92. For<br/>example, if the fluid includes particulate matter, fluid outlet port 90<br/>may be positioned to receive particles having a first particle sized<br/>distribution. First cyclone 94 may be provided in fluid flow<br/>communication with first outlet port 90 for separating some or all of<br/>the particles from the fluid. Similarly, fluid outlet port 92 may be<br/>positioned to receive a portion of the fluid containing particles having<br/>a different particle sized distribution and second cyclone 96 may be<br/>provided to remove some or all of these particles from the fluid.<br/> Generally, cyclones are effective to efficiently remove<br/>particles over a limited particle size distribution. By utilizing a prandtl<br/>layer turbine to provide streams having different particle size<br/>distributions, each of cyclones 94, 96 may be configured to efficiently<br/>separate the particles which will be received therein from the fluid. It<br/>will be appreciated that a plurality of such cyclones 94, 96 may be<br/>provided. Each cyclone 94, 96 may be of any particular design known<br/>in the art. Further, they may be the same or different.<br/> It will be appreciated that while several improvements in<br/>prandtl layer turbines have been exemplified separately or together<br/>herein, that they may be used separately or combined in any<br/>permutation or combination. Accordingly, for example, the turbines,<br/>whether nested or in series, may have varying inner and/or outer<br/>diameters. Further, any of the prandtl layer turbines disclosed herein<br/>may have a curved or spiral outlet 62. Further, if a central air inlet 60 is<br/>utilized as disclosed in Figures 10 and 11, two fluid outlet ports having<br/>the same or differing curvature may be employed or, alternately, all or<br/>a portion of each of the outlets 62 may extend in a straight line. It will<br/>further be appreciated that even if a series of nested turbines are<br/>utilized to pressurize the fluid, that an inlet fan member 68 may also<br/>be incorporated into the design. Further, any of the prandtl layer<br/>turbines disclosed herein may have an outlet fan member 70. These<br/><br/> CA 02258419 1999-O1-08<br/>-30-<br/>and other combinations of the embodiments disclosed herein are all<br/>within the scope of this invention.<br/> Prandtl layer turbines may be used in any application<br/>wherein a fluid must be moved. Further, a prandtl layer turbine may<br/>be used to convert pressure in a fluid to power available through the<br/>rotational movement of a shaft.<br/> In one particular application, a prandtl layer turbine may<br/>accordingly be used to assist in separating two or more fluids from a<br/>fluid stream or in separating particulate matter from a fluid stream or<br/>to separate particulate matter carried in a fluid stream into fluid<br/>streams having different particle sized distributions or a combination<br/>thereof (Figures 20 and 21).<br/> A further particular use of such a prandtl layer turbine<br/>may be as the sole particle separation device of a vacuum cleaner or,<br/>alternately, it may be used with other filtration mechanisms (eg. filters,<br/>filter bags, electrostatic precipitators and/or cyclones) which may be<br/>used in the vacuum cleaner art.<br/> Referring to Figure 22, a vacuum cleaner including a<br/>prandtl layer turbine is shown. In this embodiment, vacuum cleaner<br/>100 includes a first stage cyclone 102 having an air feed passage 104 for<br/>conveying dirt laden air to tangential inlet 106. First stage cyclone 102<br/>may be of any particular design known in the industry. The air travels<br/>cyclonically downwardly through first stage cyclone 102 and then<br/>upwardly to annular space 108 where it exits first stage cyclone 102. It<br/>will be appreciated by those skilled in the art that cyclone 102 may be of<br/>any particular orientation. Generally, a first stage cyclone may remove<br/>approximately 90% of the particulate matter in the entrained air.<br/> The partially cleaned air exiting first stage cyclone 102 via<br/>annular space 108 may next be passed through a filter 110. Filter 110<br/>may be of any design known in the art. For example, it may comprise<br/>a mesh screen or other filter media known in the art. Alternately, or<br/><br/> CA 02258419 1999-O1-08<br/>-31-<br/>in addition, filter 110 may be an electrostatic filter (eg. an electrostatic<br/>precipitator). In such an embodiment, the electrostatic filter is<br/>preferably be designed to remove the smallest particulate matter from<br/>the entrained air (eg. up to 30 microns). In another embodiment, the<br/>air may be passed instead to one or most second cyclones. In a further<br/>alternate embodiment, the air may be passed before or after the one or<br/>more second cyclones through filter 110.<br/> The filtered air may then passes next into inlet 60 of<br/>prandtl layer turbine 10. Depending upon the efficiency of the cyclone<br/>and the filter (if any) and the desired level of dirt removal, the prandtl<br/>layer turbine may be used to provide motive force to move the dirty<br/>air through the vacuum cleaner but not to itself provide any dirt<br/>separation function. The prandtl layer turbine is preferably positioned<br/>in series with the cyclone such that the air exiting the cyclone may<br/>travel in a generally straight line from the cyclone to the prandtl layer<br/>turbine. If the vacuum cleaner is an upright vacuum cleaner, then the<br/>prandtl layer turbine is preferably vertically disposed above the air<br/>outlet from the cyclone. If the vacuum cleaner is a canister vacuum<br/>cleaner, then the prandtl layer turbine is preferably horizontally<br/>disposed upstream of the air outlet from the cyclone.<br/> Subsequent to its passage trough the prandtl layer turbine,<br/>the air may be passed through filter 110 and/or one or more second<br/>cyclones in any particular orders. Further, in any embodiment, prior to<br/>exiting the vacuum cleaner, the air may be passed through a HEPATM<br/>filter.<br/> In an alternate embodiment, the prandtl layer turbine may<br/>also function as a particle separator. For example, in the embodiment<br/>of Figure 22, the prandtl layer turbine of Figure 21 has been<br/>incorporated. Prandtl layer turbine 10 separates the particulate matter<br/>into two streams having different particle size distributions. These<br/>streams separately exit prandtl layer turbine 10 via outlets 90, 92 and<br/><br/> CA 02258419 1999-O1-08<br/>-32-<br/>are fed tangentially into cyclones 94, 96. The cleaned air would then<br/>exits cyclones 94, 96 via clean air outlets 112. This air may be further<br/>filtered if desired, used to cool the motor of the vacuum cleaner or<br/>exhausted from the vacuum cleaner in any manner known in the art.<br/> It will be appreciated that these embodiments may also be<br/>used to separate solid material from any combination of fluids (i.e.<br/>from a gas stream, from a liquid stream or from a combined liquid and<br/>gas stream). Further, these embodiments may also be used to separate<br/>one fluid from another (eg. a gas from a liquid or two liquids having<br/>differing densities).<br/> In a further particular application, two prandtl layer<br/>turbines may be used in conjunction whereby a first prandtl layer<br/>turbine is used as a motor and a second prandtl layer turbine is used as<br/>a fan/pump to move a fluid. The prandtl layer turbine which is used<br/>as a motor is drivingly connected to provide motive force to the<br/>second prandtl layer turbine. An example of such an embodiment is<br/>shown in Figure 23. In Figure 23, reference numeral 10' denotes the<br/>prandtl layer turbine which is used as a motor (the power producing<br/>prandtl layer turbine). Reference numeral 10 denotes the prandtl layer<br/>20 turbine which is used as a fan/pump (the fluid flow causing element).<br/> Each prandtl layer turbine 10, 10' may be of any particular<br/>construction known in the art or described herein. Further, each<br/>prandtl layer turbine 10, 10' may be of the same construction (eg.<br/>number of discs, size of discs, shape of discs, spacing between discs,<br/>inner diameter of discs, outer diameter of discs and the like) or of<br/>different constructions. It will be appreciated that the configuration of<br/>each prandtl layer turbine 10, 10' may be optimized for the different<br/>purpose for which it is employed.<br/> A first fluid is introduced through inlet port 60' into<br/>prandtl layer turbine 10'. The passage of fluid through prandtl layer<br/>turbine 10' causes spaced apart members 12' to rotate thus causing shaft<br/><br/> CA 02258419 1999-O1-08<br/>-33-<br/>20 to rotate. The fluid exits prandtl layer turbine 10' through, for<br/>example, outlet 62' which may be of any particular construction<br/>known in the art or described herein.<br/> The fluid introduced into prandtl layer turbine 10' may be<br/>a pressurized fluid which will impart motive force to spaced apart<br/>members 12'. Alternately, or in addition, fluid 10 may be produced by<br/>the fluid expanding as it passes through prandtl layer turbine 10'. For<br/>example, if prandtl layer turbine 10' has a substantial pressure drop,<br/>then another source of fluid for prandtl layer turbine 10' may be a<br/>pressurized liquid which expands to a gas as it travels through prandtl<br/>layer turbine 10' or a pressurized gas which expands as it travels<br/>through prandtl layer turbine 10. The fluid may also be the<br/>combustion product of a fuel. The fuel may be combusted upstream of<br/>prandtl layer turbine 10' or within prandtl layer turbine 10'. The<br/>combustion of the fluid will produce substantial quantities of gas<br/>which must travel through prandtl layer turbine 10' to exit via outlet<br/>62'. Another source of fluid for prandtl layer turbine 10' may be<br/>harnessing natural fluid flows, such as ocean currents, ocean tides, the<br/>wind or the like.<br/> As a result of the passage of a fluid through prandtl layer<br/>turbine 10', motive force is obtained which may then be transmitted to<br/>prandtl layer turbine 10. As shown in Figure 23, spaced apart members<br/>12 of prandtl layer turbine 10 are mounted on the same shaft 20 as<br/>spaced apart members 12' of prandtl layer turbine 10'. However, it will<br/>be appreciated that prandtl layer turbine 10', and 10 may be coupled<br/>together in any manner which would transmit the motive force<br/>produced in prandtl layer turbine 10' to the spaced apart members 12 of<br/>prandtl layer turbine 10. For example, each series of spaced apart<br/>members 12, 12' may be mounted on a separate shaft and the shafts<br/>may be coupled together by any mechanical means known in the art<br/>such that prandtl layer turbine 10' is drivingly connected to prandtl<br/><br/> CA 02258419 1999-O1-08<br/>-34-<br/>layer turbine 10.<br/>Prandtl layer turbine 10 has an inlet 60 which is in fluid<br/>flow connection with a second fluid. The rotation of shaft 12 will<br/>cause spaced apart members 12 to rotate and to draw fluid through<br/>inlet 60 to outlet 62. Accordingly, prandtl layer turbine 10' may be used<br/>as a pump or a fan to cause a fluid to flow from inlet 60 to outlet 62.<br/> Depending upon the power input via shaft 20 to prandtl layer turbine<br/>10, the fluid exiting prandtl layer turbine 10 via outlet 62 may be at a<br/>substantial elevated pressure.<br/> Accordingly, prandtl layer turbine 10' functions as a motor<br/>and may be powered by various means such as the combustion of fuel.<br/> Accordingly, prandtl layer turbine 10' produces power which is<br/>harnessed and used in prandtl layer turbine 10 for various purposes.<br/> Referring to Figures 24 and 25, a prandtl layer turbine<br/>which may be used to produce motive force from a naturally moving<br/>fluid (such as wind or an ocean current or a tide) is shown. In this<br/>embodiment, prandtl layer turbine 10 (which may be of any particular<br/>construction) is provided with a fluid inlet 124 (for receiving wind or<br/>water). The entry of the fluid through inlet port 124 causes spaced<br/>apart members 12 to rotate. In this embodiment, the fluid would<br/>travel radially inwardly along spaced apart members 12 from the outer<br/>edge 42 to inner edge 40. The fluid would then travel downstream<br/>through central opening 22 to fluid outlet 126. The rotation of spaced<br/>apart members 12 by the fluid would cause shaft 20 to rotate. Shaft 20<br/>exits from prandtl layer turbine 10 and provides a source of rotational<br/>motive force which may be used in any desired application (eg.<br/>electrical generation and pumping water).<br/> Prandtl layer turbine is preferably rotatably mounted so as<br/>to align inlet 124 with the direction of fluid flow so that the fluid is<br/>directed into prandtl layer turbine 10. It will also be appreciated that<br/>inlet 124 may be configured (such as having a funnelled shape or the<br/><br/> CA 02258419 1999-O1-08<br/>-35-<br/>like) to capture fluid and direct it into spaced apart members 12. In<br/> Figure 24, prandtl layer turbine 10 is positioned vertically on support<br/>member 120. It will be appreciated that prandtl layer 10 may also be<br/>horizontally mounted (or at any other desired angle).<br/>5 Tail 122 may be provided on ring 18 and positioned so as<br/>to align inlet 124 with the fluid flow. Tail 122 may be constructed in<br/>any manner known in the art such that when the portion of the fluid<br/>which does not enter prandtl layer turbine 10 passes around ring 18,<br/>tail 122 causes opening 124 to align with the direction of the fluid flow<br/>thereby assisting in maintaining opening 124 aligned with the fluid<br/>flow as the direction of fluid flow changes.<br/>
