Abstract:
A support tower, particularly for a wind turbine. The support tower has at least a first elongated component which is internally hollow and at least a second elongated component which is slidably coupled to the at least a first elongated component and movable relative to the at least a first elongated component at least between a retracted position. The second elongated component is at least partially inserted in the at least a first elongated component, and an extracted position, where the at least a second elongated component is substantially extracted from the at least a first elongated component. A moving device for moving the second elongated component from the retracted position to the extracted position, and vice versa, and a blocking device configured to allow the at least a second elongated component to be blocked in the extracted position, are also provided.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Field of the Invention 
         [0002]    The present invention relates to a support tower, particularly for a wind turbine. 
         [0003]    More specifically, the invention concerns a support tower, particularly for an offshore wind turbine. 
         [0004]    Support tower suggested according to the invention can be in any case conveniently used to support also different very heavy apparatuses different from a wind generator, to be installed offshore at a set height with respect to the sea level, such as a military monitoring unit, or a power generator. 
         [0005]    Brief Discussion of the Related Art 
         [0006]    In the following, the specification will be addressed to the installation of an offshore wind generator, but it is well evident that the same must not be considered limited to this specific application, being the same support tower applicable also to any kind of wind system, or for ground wind systems. 
         [0007]    Growing needing of obtaining always bigger outlet power from wind generators requires the use of blades having remarkable dimensions and weight, and consequently support structures, or support towers that are resistant and obviously higher than the blade length. 
         [0008]    Installation offshore of wind systems with large power therefore requires handling and use of cranes and large other lifting means that can lift and place in the proper position towers realised to sustain wind generators and their blades. 
         [0009]    Standard techniques for installation offshore of wind systems—i.e. wind turbines—provided, after the installation of the foundation structure on ocean floor and transportation of support tower to the installation site, overturning of the latter from a horizontal position, corresponding to the position in which it is transported, to the vertical operative position. 
         [0010]    Said method for installing a wind tower requires the use of a ship provided with a crane having a loading arm longer than the height of the tower to be installed, in order to permit vertical positioning of the latter. 
         [0011]    Further, to install a traditional wind tower under safety conditions, it is necessary, before relevant overturning, perfectly stabilizing the ship provided with the lifting crane with respect to sea surface. 
         [0012]    The use of the above mentioned operative means to install traditional wind towers is however particularly expensive and strongly influenced by weather—climatic conditions. 
         [0013]    For example, it is noted that rental of a ship provided with a crane to install a traditional wind tower of about 120 m height involves the payment of many thousands of Euros. 
         [0014]    Therefore, taking into consideration very high installation costs by presently available technologies, it is often considered not convenient installing offshore a large power wind system, since economic advantages deriving from the same would be strongly limited by high costs for its installation. 
       SUMMARY OF THE INVENTION 
       [0015]    On the contrary, support tower suggested according to the present invention has such structural and functional features not requiring for its installation in situ the use of a ship provided with a crane or with other large lifting means. 
         [0016]    In view of the above, it is therefore object of the present invention that of providing a support tower, particularly for a wind turbine, that can support a wind generator, or a shuttle having a large output power, or a different heavy apparatus. 
         [0017]    Another object of the present invention is that of providing a support tower, particularly for a wind turbine, permitting its installation without the use of outer lifting and positioning means. 
         [0018]    A further object of the invention is that of providing a support tower, particularly for a wind turbine, that can be manufactured, transported and installed in situ with low expenses. 
         [0019]    Another object of the present invention is that of providing a support tower, particularly for a wind turbine, that can be installed quickly. 
         [0020]    It is therefore specific object of the present invention a support tower, particularly for a wind turbine, wherein said support tower comprises: at least a first elongated component, which is internally hollow; at least a second elongated component, which is slidably coupled to said at least a first elongated component and movable relative to said at least a first elongated component at least between a retracted position, where said second elongated component is at least partially inserted in said at least a first elongated component, and an extracted position, where said at least a second elongated component is substantially extracted from said at least a first elongated component; moving means for moving said second elongated component from said retracted position to said extracted position, and vice versa; and blocking means configured to allow said at least a second elongated component to be blocked in said extracted position. 
         [0021]    Preferably, according said blocking means comprise a plurality of pins arranged between said at least a first elongated component and said at least a second elongated component and selectively movable between a disengagement position, wherein said at least a second elongated component is movable relative to said at least a first elongated component, and an engagement position, wherein said at least a second elongated component is fixed relative to said at least a first elongated component. 
         [0022]    Advantageously, according to the invention, said support tower can comprise longitudinal guide means for guiding motion of said at least a second elongated component between said retracted position and said extracted position and for preventing reciprocal rotation of said at least a second elongated component and said at least a first elongated component. 
         [0023]    Furthermore, according to the invention, said moving means can comprise at least one lifting device comprising: a first coupling member, which is slidably connected with said longitudinal guide means and selectively fixable to said longitudinal guide means; a second coupling member, which is connected with said at least a second elongated component and slidably connected with said longitudinal guide means, wherein said second coupling member is selectively fixable to said longitudinal guide means; and at least one linear thrust member connected with said first coupling member and said second coupling member, wherein said at least one linear thrust member is selectively configurable between a minimum linear extension configuration, wherein said first coupling member and second coupling member are arranged each other at a first distance, and a maximum linear extension configuration, wherein said first coupling member and second coupling member are arranged each other at a second distance larger than said first distance. 
         [0024]    Still according to the invention, at least one linear thrust member can comprise at least one hydraulic jack. 
         [0025]    Preferably, according to the invention, a plurality of longitudinal holes can be formed in said longitudinal guide means (said first coupling member can comprises a fixing pin, which is movable between an engagement position, wherein said fixing pin engages a hole of said plurality of longitudinal holes, and a disengagement position, wherein said fixing pin is disengaged with said plurality of longitudinal holes. 
         [0026]    Advantageously, according to the invention, said moving means can comprise: a first plurality of pulleys connected with said at least a first elongated component; a second plurality of pulleys connected with said at least a second elongated component; at least one rope wrapped on said first plurality of pulleys and said second plurality of pulleys; and at least one pulling device configured to pull said at least one rope such as to move said at least a second elongated component from said retracted position to said extracted position. 
         [0027]    Furthermore, according to the invention, said support tower can comprise an anti-falling system which comprise: at least one longitudinal element longitudinally fixed to an inner part of said at least a first elongated component, a plurality of longitudinal holes being formed in said at least one longitudinal element; at least one sliding member, which is fixed to an outer part of said at least a second elongated component and slidably coupled to the at least one longitudinal element; a plurality of pins, each movable between a respective position of engagement with a hole of said plurality of longitudinal holes, and a respective position of disengagement with a hole of said plurality of longitudinal holes; at least one inserting member fixed to said at least one sliding member such that, when said at least one sliding member moves from said retracted position to said extracted position, said at least one inserting member moves, in a sequential way from bottom upwards, pins of said plurality of pins from respective disengagement position to respective engagement position, this preventing said second elongated component from falling when said support tower is vertically arranged. 
         [0028]    Still according to the invention said at least one inserting member (comprises a covering layer configured to contact pins of said plurality of pins, said covering layer being made from polyzene. 
         [0029]    Preferably, according to the invention, said anti-falling system can comprise a pneumatic removing system configured to pneumatically command movement of pins of said plurality of pins from respective engagement position to respective disengagement position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The present invention will be now described, for illustrative, but not limitative purposes, according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein: 
           [0031]      FIG. 1  shows an offshore wind system provided with a foundation structure, a wind generator and a support tower to support the wind generator, according to the present invention, in its extended operative condition; 
           [0032]      FIG. 2  shows the foundation structure of the wind system shown in  FIG. 1 , placed on ocean floor; 
           [0033]      FIGS. 3 and 4  shown two different moments of transfer of the assembly comprised of wind generator and support tower according to the present invention in its retracted configuration, from the taking zone to the ship for transportation to the installation site; 
           [0034]      FIG. 5  shows the transportation step of the assembly shown in  FIGS. 3 and 4  to the installation site; 
           [0035]      FIG. 6  shows the transportation step of the assembly shown in  FIGS. 3, 4 and 5  from the transportation ship above the foundation structure installed before on the ocean floor; 
           [0036]      FIG. 7  shows a support tower according to a first embodiment of the present invention, in a retracted configuration; 
           [0037]      FIG. 8  shows a support tower according to a first embodiment of the present invention, in an extended configuration; 
           [0038]      FIG. 9  shows a lower fixed portion of the support tower shown in  FIGS. 7 and 8 ; 
           [0039]      FIG. 10  is a partial cut-away view of a bottom part of the fixed portion shown in  FIG. 9 ; 
           [0040]      FIG. 11  is a partial cut-away view of a top part of the fixed portion shown in  FIG. 9 ; 
           [0041]      FIG. 12  shows an upper movable portion of the support tower shown in  FIGS. 7 and 8 ; 
           [0042]      FIG. 13  is a partial cut-away view of a bottom part of the movable portion shown in  FIG. 12 ; 
           [0043]      FIG. 14  is a partial cut-away view of a top part of the movable portion shown in  FIG. 12 ; 
           [0044]      FIG. 15  is a section view of a region of the support tower shown in  FIGS. 7 and 8 , wherein the fixed portion and the movable portions overlap each other; 
           [0045]      FIG. 16  is a cut-away view of the region shown in  FIG. 15 ; 
           [0046]      FIG. 17  is a partial view of a support tower according to a second embodiment of the present invention, in an initial step of its in situ installation; and 
           [0047]      FIG. 18  is a partial view of a support tower according to a second embodiment of the present invention, in the final step of its in situ installation. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0048]    In the different figures, similar parts will be indicated by the same reference numbers. 
         [0049]    Making now reference to  FIGS. 1-16 , by reference number  1  it is indicated, as an assembly, a wind system for generation of electric power, i.e. a wind turbine, substantially comprising a foundation base  2 , a support tower  3  and a wind generator  4 , the latter comprising a series of wind blades  5 , in this case namely three blades. 
         [0050]    Foundation base  2  is comprised of a tripod  6 , made up of a central tubular element  7 , from which three appendixes  7   a ,  7   b ,  7   c  extend, like a rays-assembly, with the relevant tip zones providing three through holes suitable for housing a corresponding number of foundation poles  8   a ,  8   b ,  8   c.    
         [0051]    A first flange  9  is provided at the top of said central tubular element  7 , for connection with the support tower  3 . 
         [0052]    Instead, support tower  3  has a telescopic structure, comprising a lower tubular element  10 , having a length of about 60 m, and an upper tubular element  11 , having a length of about 70 m, and realised to slide within said lower tubular element  10 , so as to be able to move from a maximum retraction position (see  FIG. 7 ) and a maximum extension position (see  FIG. 8 ). 
         [0053]    A second flange  13  is provided in correspondence of the lower end of the lower tubular element  10 , having dimensions corresponding to the first flange  9  of the support tower  3 , to permit fixing of said lower tubular element  10  to the latter. 
         [0054]    On the inner wall of the lower tubular element  10  run, from the bottom to the top of the latter, four longitudinal guides  12   a ,  12   b ,  12   c ,  12   d , equidistant each other, i.e. at angular distances of 90° each other, and having a substantially T-shaped transverse profile. 
         [0055]    A relevant plurality of holes  14   a ,  14   b ,  14   c  (plurality of holes on longitudinal guide  12   d  is not shown) is provided on each longitudinal guide  12   a ,  12   b ,  12   c ,  12   d.    
         [0056]    Instead, a fixing device  15  having an annular shape is provided at the top of the lower tubular element  10 , to permit the fixing of the upper tubular element  11  to the above lower tubular element  10 . 
         [0057]    Said fixing device is provided with a plurality of hydraulically tightening radial pins  16 , movable between a release position, in which they are contained within the structure of the fixing device  15 , and a tightening position, wherein they project from said fixing device  15  inward the lower tubular element  10 . 
         [0058]    Instead, a section reducer  11   b , comprised of a truncated cone shape tubular portion, an upper tubular portion  11   c  and a fifth wheel  29 , are instead provided on the upper part of said upper tubular element  11 , to permit connection of wind generator  4  to the top of the upper tubular element  11 . 
         [0059]    A connection ring  17  is further provided within the upper tubular element  11 , on which a plurality of holes  18 , circumferentially provided about said connection ring  17  and sized to receive said tightening radial pins  16 , when in the relevant tightening position. 
         [0060]    A tubular portion  11   a  of a set length is provided between the connection ring  17  and the lower end of the upper tubular element  11 , suitable for promoting stability and aligning said upper tubular element  11 , when in the maximum extension position, with respect to the lower tubular element  10 . 
         [0061]    Four abutment elements  19  are fixed on the outer surface of the tubular portion  11   a , placed at 90° each other and so configured to sliding coupling with above longitudinal guides  12   a ,  12   b ,  12   c ,  12   d  of the lower tubular element  10 . 
         [0062]    Four pairs of eyebolts  21   a ,  21   d  (the other two pairs are not shown in the figures) are fixed in correspondence of the lower edge of the upper tubular element  11 , provided at 90° each other and respectively aligned with respect to said abutment elements  19 . 
         [0063]    Support tower  3  comprises four lifting devices  22   a ,  22   b ,  22   c ,  22   d , under the upper tubular element  11  and respectively connected to said four pairs of eyebolts by relevant hinges. 
         [0064]    Each lifting device  22   a ,  22   b ,  22   c ,  22   d  comprises lower plate  23  and an upper plate  24 , both having a substantially “C” shaped cross section, so as to embrace a relevant longitudinal guide  12   a ,  12   b ,  12   c ,  12   d , being always slidable with respect to the same. 
         [0065]    A first hydraulic jack and a second hydraulic jack  26  are further provided in each lifting device  22   a ,  22   b ,  22   c ,  22   d , which are connected each other and linked to said lower plate  23  and to said upper plate  24 . 
         [0066]    A lower blocking member  27  and an upper blocking member  28  are respectively provided in said lower plate  23  and upper plate  24 , provided with relevant selectively movable connection pins, by a control system, between a disengagement position and an engagement position, with through holes realised in the above longitudinal guides, so that, when a connection pin is in the engagement position, relevant plate is rigidly connected with the relevant longitudinal guide, and that, when said connection pin is in the disengagement position, relevant plate can freely slide along the relevant longitudinal guide. 
         [0067]    An upper pair of eyebolts  19  projects from the top of the upper plate  24 , configured to be coupled, by hinges, with one of said pairs of eyebolts  21   a ,  21   d  provided in the upper tubular element  11 . 
         [0068]    To install the wind system  1  offshore, it is preliminarily necessary anchoring said foundation base  2  to the ocean floor by sinking of foundation poles  8   a ,  8   b ,  8   c  within the ground. 
         [0069]    After sinking of said poles, levelling of foundation base  2  is carried out, by an oleo-dynamic jack system. 
         [0070]    After having checked vertical position of foundation base  2 , relevant cemetation is carried out. 
         [0071]    Then, assembly comprising support tower  3  and wind generator  4 , with its wind blades  5 , assembled beforehand with the yard, is transported, by suitable shipping means and with the support tower  3  vertically provided in its maximum retraction configuration (see  FIGS. 3, 4 and 5 ), to the installation site, where fixing operation of the lower tubular element  10  onto first flange  9  of foundation base  2  projecting from the water free surface is carried out. 
         [0072]    Once fixed the support tower  3  onto the foundation base  2 , elevation of the latter is started, activating said four lifting devices  22   a ,  22   b ,  22   c ,  22   d , after having first deactivated the fixing device  15 . 
         [0073]    Said lifting devices  22   a ,  22   b ,  22   c ,  22   d  have a “step-by-step” operation, thus permitting raising of upper tubular element  11  from maximum retraction configuration to maximum extension configuration by subsequent raising steps, each step providing a linear stroke of about 1 mm. 
         [0074]    More specifically, each raising step provides, ins sequence, fixing of each upper plate  24  to the relevant longitudinal guide, by activating the upper blocking member  28 , compression of relevant jacks  25 ,  26  from their maximum expansion configuration with consequent rising of lower relevant plate  23 . 
         [0075]    Now, when said jacks  25 ,  26  are in their compressed configuration, lower plate  23  of each lifting device  22   a ,  22   b ,  22   c ,  22   d  is fixed to the relevant longitudinal guide, by activating the lower blocking member  27 . 
         [0076]    Then, the upper plate  24  of each lifting device  22   a ,  22   b ,  22   c ,  22   d  is disengaged from the relevant longitudinal guide, by deactivation of the upper blocking member  28 , and extension of jacks of lifting device is controlled, thus raising the upper plate  24 . 
         [0077]    Thus, repeating different times the above operative steps of each rising step, support tower  3  will gradually pass from the maximum retraction configuration to the maximum extension configuration. 
         [0078]    Once the support tower  3  is in its maximum extension configuration, taking the wind generator  4  and the relevant wind blades  5  at the design height, activation of the fixing device  15  is realised, and thus blocking of the upper tubular element  11  on the lower tubular element  10 . 
         [0079]    Thus, when the upper tubular element  11  is in its maximum extraction configuration with respect to the lower tubular element  10 , support tower  3  reaches a total height of about 130 m on the water free surface, thus permitting the use of very long wind blades  5 . 
         [0080]    Making now specific reference to  FIGS. 17 and 18 , by reference number  30  it is indicated a support tower according to a second embodiment of the present invention, for a wind generator (not shown), in a wind turbine. 
         [0081]    Also in this case, support tower  30  is comprised of a fixed lower tubular element  31  and of a movable upper tubular element  32 , sliding connected with said lower tubular element  31 , more specifically by a telescopic coupling. 
         [0082]    A coupling flange  33  is provided at the base of the lower tubular element  31  to permit coupling with a foundation base (not shown) already fixed to the ocean floor. 
         [0083]    Coupling flange  33  is provided with a plurality of pins  34 , radially provided about said coupling flange  33  and movable between a retracted release position and an extracted coupling position, wherein flange  33  is fixedly coupled with a corresponding flange of the foundation base. 
         [0084]    An annular flange  35  is fixed on the top of the lower tubular element  31 , within which the upper tubular element  32  is movably provided. 
         [0085]    A first plurality of pulleys  36  is provided on the lower portion of the annular flange  35 , circumferentially and each one linked on a relevant support element  37 , projecting below the above annual flange  35 . 
         [0086]    In correspondence of the lower part of the movable upper tubular element  32  it is instead provided a plurality of support brackets  38 , circumferentially placed about said upper tubular element  32 . 
         [0087]    A pulley of a second plurality of pulleys  39  faced upward is linked on each bracket of said plurality of support brackets  38 . 
         [0088]    A steel cable  40  is wound around the first plurality of pulleys  36  and the second plurality of pulleys  39 , with its ends connected to a lifting which (not shown), provided in correspondence of the base of the support tower  30 . 
         [0089]    As an alternative, said winch could be installed on barge for transportation of support tower  30  to the sea site of its installation. 
         [0090]    A positioning flange  32 ′ is mounted in correspondence of the lower part of the upper tubular element  32 , suitable for abutting and coupling with the annular flange  35  of the lower tubular element  31  when the above upper tubular element  32  is provided in its maximum extraction position. 
         [0091]    A blocking system  41  is further provided on the lower portion of the upper tubular element  32 , suitable for blocking each other lower tubular element  31  and upper tubular element  32 , when the latter is in its maximum extraction position with respect to the lower tubular element  31 . 
         [0092]    Blocking system  41  is comprised of a plurality of tightening hydraulic devices  42 , placed along a circumference within the upper tubular element  32 . 
         [0093]    Each tightening hydraulic device  42  comprises a tightening pin  43 , connected to a hydraulic control system that can hydraulically control its movement between a release retracted position and a blocking extracted position. 
         [0094]    Particularly, said blocking system  41  operates in such a way that, when the upper tubular element  32  is in its maximum extracted position and displacement of relevant tightening pins is input, from their retracted position to the extracted position, the latter are in a position to engage each one a corresponding seat realised on the inner wall of the lower tubular element  31 , thus causing blocking each other of upper tubular element  32  and of lower tubular element  31 . 
         [0095]    Support tower  30  also provides a safety system  44 , aimed at preventing falling downward of the upper tubular element  32  during the lifting step of the latter from the maximum retraction position to the maximum extraction position. 
         [0096]    Said safety system  44  comprises four pairs of plates  45 , having a guiding function, fixed to the inner wall by the lower tubular element  31 , and developing almost all along the longitudinal extension of the latter. 
         [0097]    Said four pairs of plates  45  are provided each other at angular distances of 90°. 
         [0098]    Each one of said pairs of plates  45  defines, between two adjacent plates, a slot, along which a sliding plate  46  can slide, fixed to the outer portion of the lower tubular element  31 , under the positioning flange  32 ′. 
         [0099]    Sliding coupling among the four sliding plates  46  and relevant pairs of plates  45 , besides guiding rising movement of the upper tubular element  32 , permits preventing rotation each other between the latter and the lower tubular element  31 . 
         [0100]    Two corresponding pluralities of longitudinal holes  47  are obtained on two plates of each pair of plates, so that pairs of holes, coaxial each other, are obtained on each pair of plates  45 . 
         [0101]    An anti fall pin  48  is aligned with each pair of holes, said pin being movable between a disengagement position, wherein it does not occupy relevant pair of holes, and an engagement position, wherein it occupies the relevant pair of holes. 
         [0102]    Said safety system  44  further comprises four insertion members  49 , fixed at the base of the upper tubular element  32  in positions under the four sliding plates  46  and having a shaped profile faced toward the anti fall pins  48  heads. 
         [0103]    Particularly, said shaped profile of each insertion member  49  has a substantially rectilinear central part, with two curved outer parts so as to gradually depart from said central part. 
         [0104]    Further, each insertion member  49  is coated, on the shaped profile side, by a polyzene layer  50 , in order to reduce friction between said insertion member  49  and the anti fall pins  48  heads. 
         [0105]    To install the support tower  30 , it is necessary, also in this case, transporting it to the installation site as described in the above with reference to support tower  3 , and connecting the same to the connection flange of the foundation base, fixed beforehand to the ocean floor. 
         [0106]    Once fixed the support tower  30  to the relevant foundation base, it is raised by activating said lifting which, the latter pulling the cable  40  and causing progressive reduction of cable  40  parts between said first plurality of pulleys  36  and said second plurality of pulley  39 , and thus progressive rising of the upper tubular element  32  up to abutment between positioning flange  32  and annular flange  35  of the lower tubular element  31 . 
         [0107]    While upper tubular element  32  moves upward, thanks to the pulling action exerted by said winch, four insertion members  49  sequentially push anti fall pins  48  within holes realised into four pairs of plates  45 , so that, in case the cable  40  fails, upper tubular element  32  fall is blocked by four sliding plates  46  and relevant four anti fall pins  48  inserted within the latter. 
         [0108]    Once the positioning flange  320 ′ of the upper tubular element  32  abuts against the annular flange  35  of the lower tubular element  31 , blocking system  41  is activated to block the upper tubular element  32  in its maximum extraction position. 
         [0109]    To bring back the support tower  30  from its maximum extraction configuration to the maximum retraction configuration, it is instead necessary activating a suitable pneumatic system provided with suitable ducts in communication with said anti fall pins  48 . 
         [0110]    When working, the above pneumatic system produces, by input of suitable compressed air pulses, sequential extraction, from top to bottom, of anti fall pins ( 48 ) from relevant holes, and thus progressive lowering of upper tubular element  32 . 
         [0111]    According to further embodiments of the present invention, not shown in the enclosed claims, the support tower can comprise, in lieu of lower  10 ,  31  and upper  11 ,  32  tubular elements described in the above, three or more tubular elements, telescopically coupled each other. 
         [0112]    The present invention has been described for illustrative, but not limitative, purposes, according to its preferred embodiments, but it is to be understood that variations and/or modifications can be introduced by those skilled in the art without departing from the relevant scope as defined in the enclosed claims.