Abstract:
A wind energy plant tower with a load-bearing tower wall, which has a circulating outer periphery and consists of a plurality of wall sections, which each one have one centre section and two border sections running in the longitudinal direction of the tower, which are provided with a plurality of connection bores, wherein the surfaces defined by the border sections run along the outer periphery or in a constant distance to the same, and the connection bores are aligned transversely to the outer periphery.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention is related to a wind energy plant tower with a load-bearing tower wall, which has a circulating outer periphery and consists of a plurality of wall sections, which each one have one centre section and two border sections running in the longitudinal direction of the tower, which are provided with a plurality of connection bores. 
         [0004]    With the increasing power capacity and magnitude of wind energy plants, the transportation and the installation of the towers impose ever-increasing problems for the wind energy plant operators. Even the cost for the production, the transportation and the installation of the towers come more and more into the focus of attention. In order to cope with this situation, towers for wind energy plants are known in the state of the art, which are subdivided into plural tower segments in the longitudinal direction. It is also known to subdivide the load-bearing tower wall into a plurality of wall sections, which result in a tower segment when they are assembled together. 
         [0005]    From WO 2004/083633 A1, the entire contents of which is incorporated herein by reference, a wind energy plant tower has become known which consists of a plurality of cylindrical or slightly conical tower segments, respectively. Each tower segment is composed of three wall sections in this. Each wall section has one flange at a time on its vertically running edges, which is provided with a plurality of connection bores. Each flange consists of a steel strip, which is connected with a wall section on the inner side of the wall section in the vicinity of the vertically running edge thereof, and extends from there in the radial direction, in an approximately right angle to the adjacent wall section. The two flanges of two neighbouring wall sections are screwed together with each other, The horizontally running edges of the wall sections are also provided with a flange, which has the shape of a ring section and extends also into the interior of the tower. Via these flanges, tower segments arranged on top of each other can be screwed together with each other. 
         [0006]    From WO 2005/075763 A2, the entire contents of which is incorporated herein by reference, a further tower for a wind energy plant has become known, the tower wall of which is composed of a plurality of wall sections. Each wall section has an essentially four-cornered shape. The border sections running in the vertical direction of the wall sections are offset into the interior of the tower in an angle of somewhat more than 90°, so that they form a flange. Via corresponding connection bores in these flanges, two neighbouring wall sections are screwed together with each other. In difference to the wall sections of the document cited above, the horizontally running edges of the essentially four-cornered border sections have no comparable flange. Instead, two wall sections arranged on top of each other are connected with each other by separate joining pieces. The joining pieces are fixed on the vertically running flanges of the wall sections. In doing so, it is also conceived to compose the wall sections offset to each other in the vertical direction. 
         [0007]    Based on this, it is the objective of the present invention to indicate a tower for wind energy plants from a plurality of wall sections, the production of which is simpler. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The wind energy plant tower according to the present invention has a load-bearing tower wall, which has a circulating outer periphery and consists of a plurality of wall sections, which each one have one centre section and two border sections running in the longitudinal direction of the tower, which are provided with a plurality of connection bores, wherein the surfaces defined by the border sections run along the outer periphery or in a constant distance to the same, and the connection bores are aligned transversely to the outer periphery. 
         [0009]    The wall sections form each one a separate structural component at a time and are connected to each other via the connection bores when the tower is installed. The wall sections are made of metal, preferably steel. The border sections with the connection bores define each at a time a surface which runs along the outer periphery of the tower wall or in a constant distance to it. Thus, the border sections are not realised as flanges which project out of the surface formed by the tower wall like in the state of the art. In particular, the border sections are not more offset against the centre sections than is preset by the desired outer periphery of the tower wall. Instead, the border sections form a uniform lateral continuation of the centre sections. Thus, the border sections run “parallel” to the outer periphery, i.e. they can run immediately along the periphery and form the same, or offset to the outer periphery. Through this, it is achieved that the border sections form an integral constituent part of the wall sections and the tower wall. Furthermore, the production of the wall sections is significantly simplified, because the wall sections do not have to be provided with a flange. Furthermore, the wall sections become more compact because there are no parts projecting out of the surface and through this, they can be transported more simply, as the case may be. The danger to damage a flange in the transportation is reduced. 
         [0010]    The connection bores are aligned transversely to the outer periphery and through this also transversely to the surface formed by the respective border sections. Preferably, the connection bores are aligned vertically to the periphery. Thus, they run essentially in the radial direction, in contrast to the connection boxes of a conventional flange connection, in which the connection bores are aligned tangentially. 
         [0011]    In the installation of the tower a corresponding number of wall sections can be connected to form a tower segment at first. The connection of the tower segments to the complete tower can be made in an arbitrary manner, in principle. A flange connection known from the state of the art as well as a connection via horizontally running border sections of the wall sections, which are shaped corresponding to the vertically running border sections, might come into consideration. The tower segments may be also connected with each other by welding. 
         [0012]    In one embodiment of the present invention, the tower has a circular or polygonal cross section. With a circular cross section, the wall sections including the border sections form cylindrical or conical partial surfaces, which have a uniform convexity. Alternatively, it is provided to give the tower a multi-corner, octahedral or polygonal cross section, for instance. In this case, the wall sections have plane surfaces, which can be offset corresponding to the multi-cornered cross section. The wall sections can then be made through edging of plane plates, which is particularly simple. 
         [0013]    In a further embodiment of the present invention, the connection bores are arranged in rows which run in the longitudinal direction of the tower. In one embodiment, the connection bores of a border section are spaced apart from each other in the perimeter direction of the tower. For instance, two rows of connection bores running in the longitudinal direction of the tower can be arranged in different distances from the vertically running edges of the border sections, Such a regular arrangement of the connection bores in a different distance from the edge of the border section permits a particularly stable connection. 
         [0014]    According to a further embodiment of the present invention, a first border section of a first wall section and a second border section of a second wall section overlap each other and a plurality of connection elements are provided, which are each at a time lead through one connection bore of the first border section and through one connection bore of the second border section, In this case, one of the border sections forms a joint piece, which overlaps the other border section. The connection elements are lead through both border sections and thus they produce a firm connection between the two border sections. The connection elements may be rivets, threaded bolts with a nut or threaded bolts which are screwed into a thread without a nut, for instance. Thus, in the embodiment with border sections overlapping each other, the two wall sections can be directly connected with each other. 
         [0015]    According to a further embodiment of the present invention, a first border section of a first wall section and a second, neighbouring border section of a second wall section are arranged side by side and are connected with each other through a joint piece which has connection bores and overlaps the first border section and the second border section. The joint piece is a separate part, like a steel ribbon for instance, which is connected by means of suitable connection elements with the connection bores of the two border sections via its own connection bores. Even though a separate component part forms the joint piece in this embodiment, the same can have a very simple form, like the wall sections. 
         [0016]    According to a further embodiment, the first border section and the second border section are spaced apart from each other in the perimeter direction. The distance between the two border sections is determined by the realisation of the joint piece and the positioning of the connection bores in the border sections and the joint piece. Through this, the edges of the wall sections and the border sections, respectively, can have greater tolerances, without that the connection or the shape of the tower are affected. 
         [0017]    In a further embodiment, the first border section and the second border section are immediately adjacent in the perimeter direction. Through the connection by a separate joint piece, the wall sections are fixed in this adjacent position. 
         [0018]    In a further embodiment, the joint piece is arranged on the outer side of the tower. Through this, the edges of the border sections are protected against weather influences by the joint piece. 
         [0019]    According to one embodiment, the joint piece extends across a border section of a wall section in the longitudinal direction of the tower, which has a plurality of connection bores. Through this, a smaller number of joint pieces are needed in order to connect the wall sections with each other. This may facilitate the installation, because less joint pieces have to be positioned. Each joint piece can be fixed with a few number of connection elements at first. This simplifies the insertion of the following connection elements. 
         [0020]    In one embodiment, the joint piece extends across the overall length of a wall section in the longitudinal direction of the tower. Through this, exactly one joint piece can be assigned to each wall section, which can be occasionally pre-mounted and transported together with the wall section. Furthermore, the number of seam positions between joint pieces arranged on top of each other is reduced. 
         [0021]    In a further embodiment, an additional joint piece is arranged on the inner side of the tower, which has connection bores and which overlaps the first border section and the second border section. In this case, each border section is kept between two joint pieces, which results in a particularly stable connection. 
         [0022]    According to a further embodiment, the connection bores in the joint piece on the outer side of the tower have threads, which co-operate with a threaded bolt which is lead from the inner side of the tower through a connection bore of a border section. The threaded bolt can be directly screwed into the joint piece. Through this, the installation is significantly facilitated, because no nut has to be attached on the outer side of the tower, which would be necessary otherwise. Instead, the threaded bolt can be introduced from out the inner side of the tower and screwed together with the joint piece, without having to hold a nut on the outer side of the tower at the same time. Accordingly, the screw pre-tension can be monitored for maintenance purposes particularly simply from out the inner side of the tower. As an additional advantage, there is a more even surface of the outer wall. 
         [0023]    In one embodiment, the joint piece has a greater thickness than the wall sections. Through this, the screw-in length necessary for a safe screwing can be obtained in the inside-threaded connection bores in the joint piece. Preferably, the thickness of the joint piece is at least 1.2 times the diameter of a connection bore. 
         [0024]    In one embodiment, the tower has a plurality of tower segments in the longitudinal direction, wherein the wall sections each extend across the length of one tower segment at a time. Thus, individual tower segments from a certain number of wall sections, which overlap only at their vertical border sections or have to be connected with the aid of a separate joint piece, can be assembled to a complete tower segment. 
         [0025]    According to one embodiment, all the wall sections of the tower or all the wall sections of a tower segment have the same shape and dimension. For instance, each tower segment may consist of three, four, five or more uniform wall sections. Through this, the production of the wall sections is significantly simplified. 
         [0026]    According to a further embodiment, the border sections of a wall section extend across the whole length of the wall section in the longitudinal direction of the tower. In principle, the border sections can also be formed only sectionwise. However, the extension across the whole length of the wall sections simplifies the manufacture of the wall sections and results in a more uniform connection with higher staunchness between the neighbouring wall sections. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0027]    In the following, the present invention is explained in more detail by means of examples of its realisation, depicted in figures. 
           [0028]      FIG. 1  shows a wind energy plant with a tower, composed of wall sections according to the present invention, in a simplified top view; 
           [0029]      FIG. 2  shows a wall section of the tower from  FIG. 1 , in a perspective view; 
           [0030]      FIG. 3  shows a cut-out of a cross section of a tower wall according to the present invention running in a horizontal plane of the tower, with two border sections overlapping each other; 
           [0031]      FIG. 4  shows a cut-out of a cross section through a tower wall according to the present invention running in a horizontal plane, with two border sections arranged in a distance from each other, which are connected with each other via two separate joint pieces; 
           [0032]      FIG. 5  shows a cut-out of a cross section running in a horizontal plane of the tower, with two border sections arranged in a distance from each other, which are connected with each other with the aid of a joint piece with threaded bores; 
           [0033]      FIG. 6  shows a cut-out of a cross section running in a horizontal plane of a polygonal tower, with two border sections arranged in a distance from each other, which are connected with each other with the aid of a joint piece with threaded bores. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0034]    While this invention may be embodied in many different forms, there are described in detail herein a specific preferred embodiment of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiment illustrated 
         [0035]    In the simplified depiction of  FIG. 1 , one recognizes a wind energy plant tower  10 , which is anchored in a foundation  12  and carries a nacelle  14  of the wind energy plant. On the nacelle, the indicated rotor  16  of the wind energy plant is fastened. The tower  10  is composed of a plurality of wall sections  18 . In the example, an equal number of wall sections  18  constitute one of three tower segments at a time, which are arranged on top of each other. In this, each wall section extends across the height of one tower segment in the vertical direction. Depending on the magnitude of the tower and other general conditions, a greater or a smaller number of tower segments can also be provided. It is also possible to compose the tower segments located on different heights from a different number of wall sections  18 . 
         [0036]    An individual wall section  18  is depicted in  FIG. 2  in a perspective view. The wall section  18  consists of steel. As the tower from  FIG. 1  is a tower tapering towards the upside with circular cross section, the wall section  18  has the shape of a cone surface segment with edges  22  linearly running in the vertical direction. Along the vertically running edges  22 , one border section  24  extends at a time, which has a plurality of connection bores  26 , arranged on top of each other in a row. Between the two border sections  24  is located a centre section  20  of the wall section  18 . The wall section  18  consists of one single steel plate, curved corresponding to the shape of the tower, which forms the centre section  20  as well as the border sections  24 . The centre section  20  passes over directly into the border sections  24 . 
         [0000]    Wall sections  18  arranged side by side can be connected with each other, in different ways. A particularly simple solution is depicted in  FIG. 3 . A first wall section  30  has a border section  32 , which has two connection bores  36  arranged in different distances from the edge  34  of the first border section  32 . The second wall section  40  has also a border section  42  with two connection bores  46  in different distances from the edge  44  of the border section  42 . The two border sections  32  and  42  overlap each other and are screwed together with each other by two threaded bolts  48  with nuts  50  arranged on the outer side of the tower wall. The wall section  40  with border section  42  and the wall section  30  with border section  32  describe a circle each at a time in the depicted cross section.
 
The outer periphery of the tower wall is constituted by the surface of the wall section  40 , situated outside with respect to the tower wall, and of the border section  42 , as well as by the outside-situated surface of the wall section  30 . Thus, the border section  42  runs directly along the outer periphery, while the inside-situated border section  32  is arranged in a constant distance to it.
 
         [0037]      FIG. 4  shows another example of realisation. In this, the two wall sections  60 ,  70  with their border sections  62 ,  72  are not arranged overlapping but in a distance from each other. Each border section has one bore  64 ,  74  at a time. A joint piece  80  located on the outer side of the tower wall consists of a steel strip, which runs along the border sections  62  and  72  and which overlaps these two border sections. The joint piece  80  is provided with two connection bores  84 , which are aligned matching the connection bores  64 ,  74  of the border sections. A second joint piece  82  is located on the inner side of the tower wall and overlaps the border sections  62 ,  72 . It is also provided with connection bores  86 , which are aligned towards the connection bores  64 ,  74  of the border sections. Two threaded bolts  88  extend through one connection bore  86  of the inner joint piece  82 , one connection bore  62  or  74 , respectively, of a border section and one connection bore  84  of the outer joint piece  80  at a time. The threaded bolts  88  are screwed together on the outer side of the tower wall with one nut  90  at a time. Through this, the wall sections  62 ,  72  are clamped in between the two joint pieces  80 ,  82 . 
         [0038]    In the additional example of realisation of  FIG. 5 , two neighbouring wall sections  100  and  110  are arranged in a distance from each other, like in the realisation example of  FIG. 4 . Via connection bores  104 ,  114 , the corresponding wall sections  102 ,  112  are screwed together with an outer joint piece  116 . The outer joint piece has two connection bores  118 , directed towards the connection bores  104 ,  114  of the border sections  102 ,  112 , which are each provided with a thread. Two threaded bolts are introduced from out the inner side of the tower wall through a connection bore  104  or  114  of a border section  102  or  112 , respectively, into a connection bore  118  of the outer joint piece  116  and fixedly screwed up there. In this way, a fixed connection of the two wall sections is also achieved. Particularly advantageous in this embodiment is that no nut has to be arranged on the outer side of the tower wall and to be fixed in the installation. In addition, a particularly even outer wall is obtained. 
         [0039]      FIG. 6  shows an additional realisation example. In the figure, the same reference signs are used as in the  FIG. 5 , when the indicated parts correspond to each other. Again, the joint piece  116  is located on the outer side of the tower wall constituted by the wall sections  100 ,  110 . The tower wall has a polygonal cross section and is chamfered in each of the regions designated with  122 . Threaded bolts  120  are lead through one connection bore  104 ,  114  in a border section of a wall section at a time, and are screwed into an interior thread in the connection bores  118  of the joint piece  116 . The thickness of the joint piece  116  is dimensioned such that a minimum screw-in length of the threaded bolts  120 , which amounts to 1.2 times the diameter of the threaded bore, is reached or exceeded, In the shown example, the thickness of the connection joint piece  116  is significantly greater than the wall thickness of the wall sections  100 ,  110 . 
         [0040]    The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims. 
         [0041]    Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other, embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim  1  should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below. 
         [0042]    This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.