Abstract:
A turbine, particularly suitable for wind generators for the production of electric power even with weak wind, is provided with four identical axial blades, opposite two by two, all of them always active, both those windward and those leeward, wherein the air collides on a vane, after having produced a thrusting torque, is conveyed to the opposite vane for generating a tail torque thanks to a series of conveying channels connecting a first vane to the opposite thereof, being also the second vane connected to the opposite thereof by another series of conveying channels, both such series of channels are orthogonal to each other and the fluid flows run through them undisturbed by any interference, with a great increase in efficiency of the turbine.

Description:
CROSSED FLOW TURBINE 
       [0001]    The present invention is related to a crossed flow wind-driven turbine, usually with a vertical axis. 
       BACKGROUND 
       [0002]    The known vertical axis wind-driven turbines generally are composed by approximately cylindrical rotor bodies, including multiple threaded variously shaped thrust vanes, whose rotation is caused by the thrust of a fluid on the surface of the vanes. 
         [0003]    The rotor turns with an axis perpendicular to the wind direction, while the axial vanes (i.e. having a height developing parallel to the rotation axis of the turbine) move according to the same direction. Typical examples are represented by the Savonius rotors. The peculiarity of these machines is their low rotation rate: the driving torque is high but the efficiency is generally poor. 
         [0004]    This typology has the remarkable advantage of not requiring to be oriented according to the wind direction. It is distinguishable by the following features: low-power applications, operation not depending on the wind direction, low cut-in rate, low noise emission level and low visual impact. 
         [0005]    In particular, the Savonius turbine exploits the canalization principle of the sole thrusting flow inside a channel determined by the coupling of only two opposed vanes, also involving a tail driving torque. 
       SUMMARY 
       [0006]    The technical problem underlying the present invention is to provide a wind-driven turbine with improved performances with respect to the known ones. Such problem is solved by a wind-driven turbine as defined in claim  1  and following. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Hereinafter, two embodiments of a turbine according to the present invention will be presented, provided to an exemplificative and non-limitative purpose, with reference to the appended drawings wherein: 
           [0008]      FIG. 1  shows the turbine as a whole, when the axis is vertically arranged, with the indication of the air flows. 
           [0009]      FIGS. 2 to 10  show the step-by-step mounting of the various parts of the turbine of  FIG. 1 . 
           [0010]      FIG. 11  shows, in the turbine of  FIG. 1 , the splitting of the air flow which, after having impacted on the vane, splits in four flows to pass through the conveying channels connecting the previous vane to opposed vanes. 
           [0011]      FIG. 12  follows  FIG. 11  to precisely indicate the various shown parts. 
           [0012]      FIG. 13  axonometrically shows in a section the arrangement of the various superimposed conveyers in the turbine of  FIG. 1 . 
           [0013]      FIG. 14  shows frontally and in a section the arrangement of the various superimposed conveyers and identifies the section plane of following  FIGS. 15 ,  16 ,  17 ,  18 . 
           [0014]      FIG. 15  shows, according to said horizontal section, the various parts composing the indicated profiles. 
           [0015]      FIG. 16  shows, according to said horizontal section, the various surfaces delimiting a conveying channel, identifying four vanes which, assembled adjacent to the conveying members, define the geometry of the conveying channels. 
           [0016]      FIG. 17  shows the flow through a conveying channel, from a vane to the opposite thereof. 
           [0017]      FIG. 18  shows the flow crossing in two orthogonal and superimposed conveying channels. 
           [0018]      FIG. 19  shows a vertical section including the horizontal axis of the conveying channels among the vanes of  FIG. 1 . 
           [0019]      FIG. 20  shows an axial section including the axis of the conveying channels among the vanes of  FIG. 1 . 
           [0020]      FIG. 21  axonometrically shows the section of  FIG. 20 . 
           [0021]      FIG. 22  axonometrically shows a conveying member. 
           [0022]      FIG. 23  shows some sections of said conveyer. 
           [0023]      FIG. 24  frontally illustrates the assembly steps for the superimposition of the conveyers. 
           [0024]      FIGS. 25 ,  26  and  27  illustrate some variants of he turbine of the previous figures. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    With reference to  FIG. 1 , a turbine  1000  is equipped with four identical vanes  800   a ,  800   b ,  800   c ,  800   d , opposed two by two, wherein the air flow or another driving fluid flow gets through a vane and get out from the opposite vane. The four vanes are kept in their seat being enclosed between a top shaped deck  300   a  and a bottom shaped deck  300   b . A moving air flow F colliding the turbine involving two adjacent vanes  800   a  and  800   b  will be split in two flows F 1 , F 2 , directed to those vanes. 
         [0026]    In connection with the vane  800   a , the flow F 1  related to it will collide on the vane itself in the first part of its path, causing an intake thrust for that vane  800   a . Subsequently ( FIG. 11 ), the flow F 1  is vertically split in four minor parallel flows F 1   a , F 1   b , F 1   c , F 1   d  to pass through the conveying channels  901   a ,  901   b ,  901   c ,  901   d  getting out of the rear part thereof, to involve at the outlet the opposed vane  800   c  which, even being leeward, is active for the tail thrust ( FIG. 17 ). 
         [0027]    With reference to the vane  800   b , the flow F 2  related to it will split into five minor parallel flows to pass through the conveying channels  902   a ,  902   b ,  902   c ,  902   d ,  902   e  (all not visible in  FIG. 1  but shown in  FIG. 20 ), getting out of the rear part thereof, to involve at the outlet the opposed vane  800   d  which, even being leeward, will be active too. 
         [0028]    It has to be noted that each of the channels  902   a ,  902   e  has a transversal section area which is the half of that of the remaining channels  902   b ,  902   c ,  902   d , and thus, even if the channels connecting the vanes  800   b  and  800   d  are five, the flow rate thereof is equal as a whole to that of the four orthogonal channels  901   a ,  901   b ,  901   c ,  901   d.    
         [0029]    The flows F 1   a , F 1   b , F 1   c , F 1   d  passing through the channels of  901  series are perpendicular to the flows F 1   a , F 2   b , F 2   c , F 2   d , F 2   e  passing through the channels of  902  series, but without any interference between such perpendicular flows because they are separately channeled, thanks to the particular geometry of said channels determined by the presence of conveying members  1201   a ,  1201   b ,  1201   c ,  1201   d ,  1201   e ,  1201   f ,  1201   g ,  1201   h  (se  FIGS. 3 to 10 ) stacked at the driven shaft  400 . 
         [0030]    The preferred embodiment of the present invention is described hereinafter, and comprises a turbine  1000  with four identical vanes  800   a ,  800   b ,  800   c ,  800   d , arranged so as to follow a polar repetition with a rotation around the axis Z  500 , whose height develops according to the axis  500  of the turbine itself. 
         [0031]    The turbine  1000  rotates at a rate W  241  around the axis  500  thereof, if collided by the wind or, more in general, if immersed in a moving fluid, called “driving fluid”  600 , coming from any direction whose directional vector has its main component comprised in the plane XY  700 , orthogonal to the axis Z  500 . The turbine comprises four identical thrust vanes  800   a ,  800   b ,  800   c ,  800   d , characterized by an approximately drop shaped wing profile  801 , the sections thereof according to a plane parallel to plane XY are each rotated of 90° degrees around axis Z with respect to each other. 
         [0032]    The projection on the plane XY of the section of each vane comprises a geometry wherein the perimeter  801  is described as follows with reference to  FIG. 3 . 
         [0033]    With reference to the vane  800   a , whose perimeter is considered proceeding counterclockwise from point  5 , a first section is provided, starting from point  5  and ending at point  6 , called “concave thrusting profile”  1 , having one or more curvature centers, commencing at point  5  more distant from axis Z  500 . 
         [0034]    Said thrusting profile is suitable to capture the driving fluid  600  flow ( FIG. 6 ) thereby receiving the thrusting pressure which, applied along the whole height  802  of the vane, produces a resulting thrusting momentum FS  221 ,  FIG. 17 , whose component on plane XY  700  perpendicular to axis Z, is far from axis Z of an amount called “arm A”  211 . Such component  700  produces a “thrust driving torque” MS  201  putting into rotation the turbine  1000 . Such “concave thrusting profile” ends at point  6  wherein the tangent thereof is parallel to one of axis X or Y (considered integral to the turbine). Point  6  is also the intersection of the sectioning plane with the segment S 1  of  FIG. 13 . 
         [0035]    Said thrusting profile  1  is prolonged, after point  6 , into the “rectilinear conveying profile”  2  parallel to one of axes X and Y and tangent to the end  6  of the “concave thrusting profile”  1  closer to axis Z. Such rectilinear conveying profile  2  starts from point  6  and ends at point  7 . The distance thereof from one of the axes of the main orthogonal directions X and Y being parallel thereto, is called “half-width of the conveyed thrusting flow”  21  and the terminal point  7  thereof, with respect to the main direction perpendicular thereto, lies at a distance  25  resulting equal to the “half-width of the conveyed thrusting flow”  21 . 
         [0036]    In the following, a “volume profile”  3  is considered, starting from point  7  and ending at point  8 , orthogonal to the preceding “rectilinear conveying profile”  2 . It is far, from one of the axes of the main orthogonal directions X and Y being parallel thereto, of a distance  25  which is equal to the “half-width of the conveyed thrusting flow”  21  and ends at point  8 , possibly jointly or not. 
         [0037]    In the following, the “flow drag convex profile”  4  is considered with ne or more curvature centers ending at the beginning of the “concave thrusting profile”  5 . It is provided to be collided against the driving fluid  600  without entrapping any fluid flow. 
         [0038]    With reference to the vane  800   a , the flow of the driving fluid is conveyed in a conduit (conveyed thrusting channel), the vertical walls thereof being composed starting from point  5  by the vertical profiles  1 ,  2 , by the wall  1207 , by the profile  3  of the vane  800   b . The remaining walls defining the conduit are the planes  1204 , Ws  1204 ′ of the lower conveyer ( FIG. 16 ) and the corresponding planes of the superimposed conveyer, not shown. The “half-width of the conveyed thrusting flow”  21  is provided so as to define a series of superimposed conveying channels  901   a ,  901   b ,  901   c ,  901   d  and/or  902   a ,  902   b ,  902   c ,  902   d ,  902   e , the width B  22  thereof being equal to the double of the “half-width A of the conveyed thrusting flow”  21  itself. The four half-channels A 1   911 , A 2   912 , B 1   921  e B 2   922  determined by the assembly of the four vanes  800   a ,  800   b ,  800   c ,  800   d  are coincident and parallel two by two and cause an “orthogonal central crossing”  931  wherein the conveyed thrusting fluid flows converge without having a mutual contact and thus without any mutual interference. In this way, a series of conveying channels  901   a ,  901   b ,  901   c ,  901   d  are determined, parallel to axis X, and a series of conveying channels  902   a ,  902 à,  902   b ,  902   c ,  902   d , parallel to axis Y. 
         [0039]    Hence, part F 1  of the driving fluid flow colliding with a first vane, e.g.  800   a , imparts a thrusting force, then enters into the series of conveying channels  901   a ,  901   b ,  901   c ,  901   d  generated by the conveyers (splitting into the flows F 1   a , F 1   b , F 1   c , F 1   d ), then is gathered getting out of them, to urge the opposed vane  800   c  with a tail thrust. The other part F 2  of the driving fluid flow F collides with the vane  800   b  orthogonal to said first vane  800   a , then it enters into the series of conveying channels  902   a ,  902   b ,  902   c ,  902   d ,  902   e  orthogonal to those mentioned before, so as to prevent any interference. The series of conveying channels  901   a ,  901   b ,  901   c ,  901   d  is arranged so as the fluid flow itself gets out of the other leg of the channel generating a “tail thrust FC”  223  on the concave wall  1  of the opposed vane  800   d  facing towards the opposite part with respect to the source of the fluid flow. The tail thrust FC, equivalent to the resulting momentum from the thrusting pressure of the tail fluid flow colliding along the whole height  802  of the vane  800   c , causes, thanks to the “tail arm C”  213  the “tail driving torque MC”  202 . The conveying tower  1200  comprises a series of conveyers  1201  ( FIGS. 7 and 8 ) identical to each other, each rotated of 90° degrees with respect to the preceding and superimposed to the latter according to axis Z  500 . Such configuration creates a series of channels identical to each other (conveying channels), each rotated of 90° degrees with respect to the preceding and superimposed to the latter. 
         [0040]    In such a way, each fluid flow coming from a series of orthogonal channels  901   a ,  901   b ,  901   c ,  901   d  and from the other series  902   a ,  902   b ,  902   c ,  902   d ,  902   e  is split and conveyed to produce at the outlet the respective tail thrust. 
         [0041]    With reference to the point f view of  FIG. 22 , the central part of each conveyer  1201  comprises a central plate  1202  having two flat faces and parallel to plane XY  700  with square geometry, the upper face called Ws and the lower face called Wi. From each of the two opposed upper sides  1223  of the perimeter of the face Ws, two sloped surfaces lead off, with the same inclined area, called conveying ramps  1204 . 
         [0042]    Each of them is the face of a prismatic body having a right-angled triangle  1224  as base and generated by the hypotenuse  1225  f said right-angled triangle. The face  1236  generated by the longer cathetus  1226  is arranged in parallel to plane XY  700  under the level of the face Wi. The face  1228  generated by the shorter cathetus  1227  is perpendicular to said plane. 
         [0043]    A prismatic body identical to the above described one is connected to each of the two opposite lower sides  1213  belonging to the lower face Wi, but arranged in a position so as the ramp  1214  leads off from said side in ascent. Therefore, the face  1206  generated by the longer cathetus  1216  is placed in parallel to plane XY  700  over the face Ws. The face  1207  generated by the shorter cathetus  1217  is perpendicular to that plane. The faces  1204  and  1214  are called deflecting ramps. The faces  1207  and  1228  are called conveying walls. Thus, the lower part of each conveyer  1201  as above described, is placed in identical manner with respect t said upper part if such conveyer is rotated of 90° degrees. Then the faces  1236  and  1206  represent the corresponding face of the above described prisms. The superimposition of more conveyers as above described, making the faces  1206  and  1236  to fit together, generate channeled orthogonal and superimposed paths (channels  901   a ,  901   b ,  901   c ,  901   d ,  902   a ,  902   b ,  902   c ,  902   d ,  902   e ) wherein the flow coming from the vanes passes. Such configuration allows the orthogonal flows to not interfere with each other. 
         [0044]    The central hole  1208  allows the alignment according o the axis with the transmission shaft  400 . In such a way, both the conveying channels can generate a “thrust driving torque” (when the fluid collides on the thrust walls at the entrance of the channel) and a “tail driving torque” (when the fluid collides onto the thrust wall at the outlet of the channel on the concave wall of the opposite vane). 
         [0045]    Two shaped decks  300  close the assembly “vanes, conveying structure” creating a sandwiched structure. The decks  300 , appropriately connected to the transmission shaft, transfer the driving torque of the turbine  1000  to the shaft itself. The transmission shaft  400  is the transfer-appointed member to any kind of end unit, of the driving torque of the turbine  1000 . 
         [0046]    In conclusion, in the above described turbine, four axial vanes  800   a ,  800   b ,  800   c ,  800   d , opposed two by two, define a channel delimited by the intradoses and by the extradoses of the vanes wherein the air flow or any other fluid flow get through a vane and get out of the opposite vane through such channel. 
         [0047]    With reference to  FIGS. 25 and 26 , a first variant of the previously described turbine is disclosed hereinafter, wherein each vane has the same profile and the same section of the four vanes  800   a ,  800   b ,  800   c ,  800   d , and further is made by the axial stacking of vane modules  801 . 
         [0048]    Each module has a connection interface  802  on the perimeter of the lower base  804 , apt to the connection to the module itself, either by a suitable interface formed on the base deck  300   a , either by a suitable interface  808  formed on the perimeter of the upper base  803 . Such configuration of the vane module allows to obtain, by the stacking of more modules, the desired axial length of the vane to obtain the proportioning of the crossed flow turbine. 
         [0049]    The interface formed on the perimeter of the upper base  803  is also apt to carry out the connection of the module itself by a suitable interface formed on the upper deck  300   b.    
         [0050]    The height H of the vane module is coupled to the height of the series of deflecting-conveying modules lying stacked on the transmission axis so as to assure the modular stacking replication and so as to assure the modular coincidence of the holes arranged for the mechanical connection between vane modules and the deflecting-conveying modules. 
         [0051]    Each vane module  801  has suitable mountings on the walls  805  and  806 , apt to the connection of the vane module itself with the adjacent deflecting-conveying module. 
         [0052]    More precisely, on the wall  805  and on the wall  806  as well, a series of holes  811  are arranged vertically aligned to be progressively used as mechanical connection at the assembly, proceeding with the subsequent stacking of the turbine components. The holes are apt to connect the walls  805 ,  806  with the wall  302  of the deflecting-conveying module. 
         [0053]    The vane module has a vertical wall  807  lying between the walls  805  and  806 . It is placed at an angle of 45° degrees with respect to the two walls and has a series of holes  812  apt to the connection of the vane module to the plane  303  of the deflecting-conveying module and through the latter to the transmission shaft  400  of the turbine. 
         [0054]    The bottom of the vane module  804  represents the structural member “reinforcing rib” of the vane at different partial heights determined by the heights of the vane modules themselves. On the bottom  804 , close to the point, a hole  809  is formed, acting as scupper hole for the discharge of the water and as passage for the tie rod  810  of the axial containment of the vane modules  801  composing the turbine. 
         [0055]    The tie rod  810  of calibrated length is top threaded to the upper deck  300   b  and bottom threaded to the base deck  300   a  so as to keep compressed the vane modules  801  between the two decks  300   b  and  300   a . Such connection occurs at the point of the vane, wherein the thrust stress is higher by the driving fluid. 
         [0056]    With reference to  FIG. 27 , a second variant of the turbine is such that each conveying-deflecting module  301  is made by the axial stacking of two identical sub-modules  302 , having a universal coupling interface for realizing the plane  303 , to be stacked axially and to be connected to the adjacent vane modules as well. 
         [0057]    The deflecting-conveying module has a central deck  1202  and two side ramps  1204 . The central deck offers a smooth surface Ws from the opposite side to the conveying ramps, while from the side Wi of the ramps, opposite to the previous one, offers a low relief  322  apt to house an annular bonding plate  341  apt to connect the vane modules by holes of the wall  307  to the turbine transmission and supporting shaft  400 . 
         [0058]    The low relief  322  has a depth of at least a half of the thickness of the plate  341 . 
         [0059]    Two deflecting sub-modules  302  are coupled facing the low relieves  322 , enclosing in the formed volume the plate  341 . 
         [0060]    On the face  323  two pairs of fastenings are provided, one male  324  and one female  325 , apt to rigidly connect the sub-modules  302  to each other. The four mountings  324  and  325  are used to trim the plate  341  so as to place the axes of the four holes  342  diagonally aligned with the holes  812  of the vane modules  801 . Such alignment allows the connection of the vane modules through the hole  812  of the wall  807  aligned with the threaded hole  342  into the plate  341 . 
         [0061]    In a further variant, both the lower deck and the upper deck are provided with an interface frame for the vane module. 
         [0062]    Having described some embodiments of the present invention, it is specified that not only such embodiment are to be protected, but the protection is extended to all the variants obtainable by the application of the explained features, as defined in the following claims.