Patent Publication Number: US-2009223139-A1

Title: Method and system for assembling components in a tower of a wind energy turbine

Description:
BACKGROUND OF THE INVENTION 
     The field of the present invention relates generally to towers used with wind turbines, and more specifically to a method and system for assembling platforms used with wind turbine towers. 
     Modern high performance wind energy turbines often include a tubular tower, with diverse operating components of the wind energy turbine located internally of the tower and at the bottom thereof. Such components or units may include the frequency converter, the transformer and/or the control systems necessary to transmit the electrical energy from the wind turbine to a power distribution grid. In at least some known towers, access to the components and units is possible via a tower door located in a wall of the tower. In the past, installation and maintenance of such components and units required them to be brought into the tower through the tower door. As a result, the size of the individual units and components or parts was limited by the size of the door opening. 
     Assembling and mounting of such components may be a time-consuming task. For example, in at least some known assembly methods, after formation of the foundation of the tower, at least one operating component of the wind energy turbine, such as at least one electrical power module, is coupled to the foundation and, thereafter, the lowermost segment of the tower is placed over the pre-mounted module. However, this assembly procedure requires some attention and effort to prevent damage of the pre-mounted module when lowering the tower segment onto the foundation. In other known assembly methods, platforms containing pre-arranged operating components are lowered into a tubular tower section that includes support elements on its inner walls at various elevations that support the platforms. While an improvement, this assembly method still requires some attention and effort to prevent damage of the prearranged platforms when lowering the platforms into the tubular tower section. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one aspect a system for assembling components in a tower of a wind energy turbine is provided. The system includes a first platform, a second platform, and at least one connector extending from the first platform. The at least one connector includes a shear block and a cap movably coupled to the shear block and movable with respect to the shear block. At least one opening is defined in a surface of the second platform, the at least one opening is configured to receive a portion of the at least one connector therein to couple the first platform to the second platform when the cap is moved from a coupling position to an anchoring position. 
     In another aspect, a method for assembling components in a tower of a wind energy turbine is provided. The method comprises extending at least one connector from a first platform, the at least one connector comprising a shear block and a cap movably coupled to the shear block and movable with respect to the shear block. The method further comprises forming at least one opening in a surface of a second platform, the at least one opening is configured to receive a portion of the at least one connector therein. The method further comprises moving the cap to a coupling position, positioning the first platform and the second platform such that the at least one opening receives the portion of the at least one connector, and moving the cap to an anchoring position, whereby the first platform is coupled to the second platform. 
     In a further aspect, a platform for a tower of a wind energy turbine is provided. The platform includes at least one connector extending from the platform. The at least one connector includes a shear block and a cap movably coupled to the shear block and movable with respect to the shear block. A portion of the at least one connector is configured to be received in an opening defined in a surface of a structural element positioned vertically adjacent the platform. The platform is configured to be coupled to the structural element when the portion of the cap is received in the opening and the cap is moved from a coupling position to an anchoring position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of an exemplary wind turbine; 
         FIG. 2  illustrates an exemplary platform for use with the wind turbine shown in  FIG. 1 ; 
         FIG. 3  illustrates an exemplary connector for use with the platform shown in  FIG. 2 ; 
         FIG. 4  illustrates an alternative orientation of an exemplary connector for use with the platform shown in  FIG. 2 ; 
         FIG. 5  illustrates two exemplary platforms positioned for assembly; and 
         FIG. 6  illustrates four exemplary platforms in an assembled orientation. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates an exemplary wind turbine  10  that includes a tower  20 , a nacelle  30  mounted to the top of tower  20 , and a rotor hub  40  mounted to nacelle  30 . Rotor blades  50  are mounted to rotor hub  40  for extracting mechanical power from the wind. 
       FIG. 2  illustrates an exemplary platform  100  that may be used with tower  20  according to an embodiment of the invention. In the exemplary embodiment, platform  100  includes a structural frame  102  that includes substantially vertical members  104  and substantially horizontal members  106 . In one embodiment, vertical members  104  and horizontal members  106  are steel beams. In the exemplary embodiment, members  104  and  106  are assembled to form a generally cube-like structure for frame  102  that is approximately three meters long on each side. Alternatively, any shape and dimensions of frame  102  may be used that enables frame  102  to function as described herein. For example, in alternative embodiments, frame  102  may include diagonal supporting members and/or other members that facilitate stabilizing and providing structural support to frame  102 . A floor  108  is coupled to frame  102  for supporting diverse operating components or units for the wind energy turbine, such as, but not limited to, a frequency converter  130 , a transformer  132 , and/or a controller  134  used to supply electrical power from wind energy turbine  10  (shown in  FIG. 1 ) to an electrical power distribution grid. 
     In the exemplary embodiment, connectors  150  extend from platform  100 . In the exemplary embodiment, only two connectors  150  are illustrated at the top of each vertical member  104 . Alternatively, more or fewer than two connectors  150  may extend from the top of each vertical member  104 . Connectors  150  securely couple platform  100  to another structural element within tower  20  that is positioned substantially vertically and adjacent to platform  100 . In alternative embodiments, connectors  150  may be disposed at any location on frame  102 , or on platform  100 , that facilitates providing sufficient structural integrity with an adjacent structural element. 
       FIGS. 3 and 4  illustrate an exemplary embodiment of a connector  150 . In the exemplary embodiment, each connector  150  includes a base  152  for mounting to a vertical member  104  and a shear block  154  mounted to base  152 . In the exemplary embodiment, base  152  is welded to vertical member  104 , and shear block  154  is welded to base  152 . Alternatively, other known methods may be used to couple base  152  to vertical member  104  and shear block  154  to base  152 . Each connector  150  in the exemplary embodiment also includes cap  156  movably coupled to shear block  154 . In the exemplary embodiment, cap  156  may rotate about a vertical axis that extends through a center of shear block  154  and cap  156 . In particular, in the exemplary embodiment cap  156  may be rotated into a coupling position  158 , in which a cross-section of cap  156  in an X-Y plane is substantially aligned with a cross-section of shear block  154  in the X-Y plane as shown in  FIG. 3 . Cap  156  also may be rotated into an anchoring position  160 , in which a cross-section of cap  156  is substantially out of alignment with a cross-section of shear block  154 , as shown in  FIG. 4 . In alternative embodiments, cap  156  may, for example, slide with respect to shear block  154  from coupling position  158  to anchoring position  160 . 
       FIG. 5  illustrates a use of connectors  150  to couple platform  100  to a second platform  200 . In an exemplary embodiment, platform  200  houses additional operating components or units for the wind energy turbine  10  (shown in  FIG. 1 ), such as, but not limited to, a frequency converter  130 , a transformer  132  and/or a controller  134  (each shown in  FIG. 2 ). Alternatively, platform  200  may be, for example, a structural component of nacelle  30  (shown in  FIG. 1 ) located above platform  100 , or an anchoring base of tower  20  (shown in  FIG. 1 ) wherein platform  200  is positioned beneath platform  100  (in which case connectors  150  may extend from a bottom surface of platform  100 ). 
     In the exemplary embodiment, a lower leg portion  202  of platform  200  is positioned substantially above and substantially adjacent to platform  100  for assembly. At least one opening  204  is defined in a surface  206  of lower leg portion  202 . Each opening  204  is sized and oriented to receive a portion of a connector  150  when platform  200  and platform  100  are positioned for assembly. In particular, when connector cap  156  is in coupling position  158 , opening  204  may receive a portion of connector  150  therein. When connector  150  is positioned within opening  204 , cap  156  is moved into anchoring position  160 , thus substantially preventing connector  150  from exiting opening  204 . As a result, when cap  156  is in anchoring position  160 , platform  100  is securely coupled to platform  200 . 
     More specifically, in the exemplary embodiment each cap  156  is in coupling position  158  prior to assembly, wherein a cross-section of each cap  156  is substantially aligned with a cross-section of its corresponding shear block  154  as illustrated in  FIG. 3 . Each opening  204  is sized and oriented to receive shear block  154  and cap  156  when in coupling position  158 , such that each opening  204  may receive a portion of each connector  150 . In the exemplary embodiment, when in coupling position, each cap  156  extends through opening  204 , and opening  204  receives a portion of shear block  154 . Once a portion of a shear block  154  is received within each opening  204 , each cap  156  is moved into anchoring position  160 , wherein a cross-section of cap  156  is not aligned with a cross-section of shear block  154 , as illustrated in  FIG. 4 . In anchoring position  160 , a cross-section of cap  156  is no longer aligned with opening  204 , and cap  156  is prevented from exiting through opening  204 . As a result, moving cap  156  into anchoring position  160  securely couples platform  100  to platform  200 . In the exemplary embodiment, cap  156  extends completely through opening  204 . In alternative embodiments, opening  204  may have a shape that enables cap  156  to move into anchoring position  160  when only a portion of cap  156  has been received in opening  204 . 
       FIG. 6  illustrates an exemplary embodiment in which four platforms  300 ,  400 ,  500  and  600  have been assembled according to the present invention. In the exemplary embodiment, a single platform  400  includes both openings  204  (not visible), for coupling to a lower adjacent platform  300 , and connectors  150  (not visible), for coupling to a higher adjacent platform  500 . Adjacent platforms such as platforms  400 ,  500  and  600  may include additional convenient features, for example ladder sections  402 ,  502  and  602  that align to form a single climbing ladder path for access to the various platforms when the platforms are coupled. In addition, an outer tower wall  700  may be mounted to platforms  300 ,  400 ,  500  and  600 . 
     The construction and design of platforms and connectors as provided according to embodiments of the invention is advantageous in that operating components may be pre-assembled on a platform prior to assembling the platform in a tower, which facilitates reducing a risk of damage to the operating components when installing the components in a tower. In addition, the use of platforms and connectors as provided according to embodiments of the invention facilitates reducing the tight manufacturing tolerances required to use conventional fasteners such as bolts and nuts, thereby facilitating reducing a cost of manufacture of the platforms. Further, the use of platforms and connectors as provided according to embodiments of the invention facilitates reducing the time required to secure platforms during field installation at heights on the order of ten meters above the ground, thereby reducing a cost and safety risk of installation. 
     It is to be noted here that the specific configuration and shape of platforms  100  and  200  and connectors  150  and openings  204  as shown in  FIGS. 2-5 , and of platforms  300 ,  400 ,  500  and  600  as shown in  FIG. 6 , are not necessary according to the invention. The invention uses some kind of connector with a movable cap or the like and an opening that receives a portion of the connector when the cap is in a coupling position, and holds the connector when the cap is in an anchoring position, to couple vertically adjacent platforms. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.