Abstract:
Assembly process of a telescopic tower ( 100 ) including at least one prefabricated concrete section, comprising the following steps: providing sections ( 2,4,6,8,10 ) in an initial position wherein superimposed sections are disposed coaxially within a base section ( 10 ); providing assembly means ( 14,16,18 ); providing operator support means ( 20 ) on the external surface of said base section ( 10 ) essentially vertically in correspondence with the upper edge of said base section ( 10 ); lifting the innermost superimposed section ( 2,4,6,8 ) radially from those that are in the initial position forming a joint between the lower end portion of said superimposed section ( 2,4,6,8 ) which is being lifted and the upper end portion of the radially external and immediately adjacent section ( 4,6,8,10 ); providing in said joint anchoring devices for immobilizing at least provisionally the corresponding sections ( 2,4,6,8,10 ) between one another.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a U.S. national phase of International Patent Application No. PCT/EP2012/074996, filed on Dec. 10, 2012. Priority under 35 U.S.C.§119(a) and 35 U.S.C.§365(b) is claimed from Spanish Patent Application No. P201131990, filed on Dec. 9, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to an assembly process of a telescopic tower, especially an assembly process of a telescopic tower including at least one prefabricated concrete section, for example a telescopic tower of prefabricated concrete sections designed to support a wind turbine. 
         [0003]    Therefore, the main sector of application of the present invention is the construction industry, especially in concrete, in combination with the renewable or green energy industry, specifically wind power. 
       BACKGROUND OF THE INVENTION 
       [0004]    The use is known of towers formed from at least two sections, including at least one prefabricated section with the purpose of supporting a wind turbine at a great height. It is also known that said sections can be modular, being generally composed of pieces in the form of tile or segments that form a tapered or truncated cone-shaped cylindrical section. The total height of a tower will be distributed between the different sections in any possible combination, i.e. all sections can have the same height, some sections may have the same height, all sections may have different heights from one another, etc. 
         [0005]    Telescopic towers have recently become known, formed from at least two coaxial sections of different diameter, optionally formed by segments. 
         [0006]    Nevertheless, the assembly processes known for these recently introduced telescopic towers are still not totally optimized. 
         [0007]    For example, document WO 2011/006526 A1 discloses an assembly process based on disposing, on the one hand, cables or tendons which connect the upper edge of each section with the lower edge of the radially inner and immediately adjacent section and, on the other hand, traction means that act on said cables or tendons to lean on the upper edge of an outer section in assembled position and pulling from the lower edge of an inner section in folded position, thus lifting said inner section to its assembled position and with it the array of inner sections interconnected with cables, and so on and so forth until completing the lifting of all sections. This document also stipulates the disposal of an operator support platform inside the tower, which is progressively raised as the assembly of the tower progresses. 
         [0008]    Bearing in mind that every time a lifting action is performed, operators have to work at the height of the joint between the upper end portion of the outer section and the lower end portion of the inner section to dispose in said joint anchoring devices to immobilize the corresponding sections between one another, this process forces the progressive rise in position of said operators and the means designed to house said operators, which can increase the number of actions associated with assembly of the tower and may lengthen the assembly time. Furthermore, the disposal of the platform inside the tower may enter in conflict with safety rules that prohibit the presence of operators under suspended loads. 
       SUMMARY OF THE INVENTION 
       [0009]    To simplify, hereinafter in the description reference will be made to towers composed of said type of tapered or truncated cone-shaped cylindrical sections, although it will be understood that the towers can also be composed of sections of oval or polygonal plan or any other suitable form. Also to simplify, hereinafter it shall be understood that the position of a section is defined by the position of its axis of revolution, i.e. that a section is in vertical position if its axis of revolution is in vertical position, that a section is in horizontal position if its axis of revolution is in horizontal position, etc. 
         [0010]    The object of the present invention is thus to provide an assembly process of a telescopic tower, especially an assembly process of a telescopic tower including at least one prefabricated concrete section, for example a telescopic tower of prefabricated concrete sections designed to support a wind turbine. 
         [0011]    More specifically, the present invention proposes an assembly process of a telescopic tower including at least one prefabricated concrete section, comprising a base section and a plurality of superimposed sections, wherein the diameter of said base section is greater than the diameter of said superimposed sections, the assembly process comprising the following steps: 
         [0012]    a) providing said sections in an initial position wherein said base section is vertically disposed resting on an assembly surface and said superimposed sections are disposed coaxially within said base section; 
         [0013]    b) providing assembly means capable of selectively lifting said superimposed sections; 
         [0014]    c) providing operator support means on the external surface of said base section essentially vertically in correspondence with the upper edge of said base section; 
         [0015]    d) lifting the innermost superimposed section radially from those that are in the initial position, by said assembly means, to an assembly position wherein the lower end portion of said superimposed section which is being lifted is situated essentially vertically in correspondence with the upper end portion of the radially external and immediately adjacent section in relation to said section which is being lifted, forming in this way a joint between the lower end portion of said superimposed section which is being lifted and the upper end portion of the radially external and immediately adjacent section in relation to said section which is being lifted, said joint being thus situated essentially vertically in correspondence with said operator support means; 
         [0016]    e) providing in said joint anchoring devices for immobilizing at least provisionally the corresponding sections between one another, by operators housed in said operator support means; 
         [0017]    f) repeating steps d) and e) at least once. 
         [0018]    The assembly process of a telescopic tower in accordance with the present invention can be carried out inversely (i.e. performing the actions opposite to those described in this step and performing the steps essentially in reverse order) in order to dismantle said telescopic tower. 
         [0019]    As can be appreciated, the assembly process in accordance with the present invention stipulates the disposal of the operator support means in a point of the assembly process at a predetermined height and enables maintaining said operator support means at the same height during the remainder of the tower assembly process. Furthermore, the operator support means are disposed on the outside of the base section, which facilitates complying with the safety legislation that prohibits the presence of operators under suspended loads. 
         [0020]    The process in accordance with the present invention can be carried out by the use of any assembly means such as, for example, a conventional moving external crane. Nevertheless, the use is preferred of assembly means which can be called “self-climbing”, i.e. installed in the tower, such as sets of cables and jacks which lift the sections leaning on other sections, hydraulic jacks that push the sections upward, rack and pinion sets that push the sections upward or similar. The assembly means may even comprise different types of devices, the first section being lifted, for example, by means of a conventional moving external crane which has been used to dispose the sections in the initial position) and lifting the remaining sections using self-climbing devices. 
         [0021]    The process in accordance with the present invention may involve guide means to guide the section which is being lifted along a predetermined trajectory, and said guide means may even include: at least one fixing member, fixed by a lower portion to the external surface of said base section so that it extends upward beyond the upper edge of said base section, at least one tensioning member which emerges from said fixing member in a position above the upper edge of said base section, and at least one displacement element disposed in the free end of said tensioning member; said tensioning member being disposed to press said displacement element against a superimposed section which is being lifted, and to guide the section in question throughout the desired trajectory. For example, said tensioning member may be of adjustable length so that it enables the guiding of sections of different diameter whilst maintaining said fixing members in the same position during the position during the process in accordance with the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    These and other characteristics and advantages of the present invention shall be revealed from the following description of an embodiment thereof, given only by way of non-limiting example, with reference to the attached drawings, wherein: 
           [0023]      FIGS. 1A ,  1 B,  1 C and  1 D show schematic elevation views of a telescopic tower, illustrating different stages of a first embodiment of the process in accordance with the present invention. 
           [0024]      FIGS. 2A ,  2 B,  2 C and  2 D show schematic elevation views of a telescopic tower, illustrating different stages of a second embodiment of the process in accordance with the present invention. 
           [0025]      FIG. 3  shows an elevation view of a detail of  FIG. 1A . 
           [0026]      FIG. 4  shows an elevation view of a detail of  FIG. 2A . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    The figures in the attached drawings are all symmetrical with respect to its central vertical axis, except for part  300 . Therefore, in the interests of clarity, parts  14 ,  16 ,  18 ,  20 ,  22 ,  24  and  26  only refer to one side of said central vertical axis, understanding that the similar parts disposed on the other side of said central vertical axis share the same references. 
         [0028]    With reference then to  FIGS. 1A ,  1 B,  1 C,  1 D and  3 , a telescopic tower  100  is illustrated that implements a first embodiment of the process in accordance with the present invention. Said telescopic tower  100  comprises a foundation with an upper assembly surface  200 , a base section  10  and four superimposed sections  2 ,  4 ,  6 ,  8 , a wind turbine  300  and a support structure  400  of sections internally fastened to said base section  10 . 
         [0029]    In this embodiment, the intermediate superimposed sections  4 ,  6 ,  8  all have straight cylinder form and the same length, the upper superimposed section  2  also has the form of a straight cylinder but it has a greater length than that of the intermediate superimposed sections  4 ,  6 ,  8 , and the base section  10  has a truncated cone shape in a main lower portion and the form of a straight cylinder in the remaining portion, the total length of said base section  10  being larger than the length of said upper superimposed section  2 . 
         [0030]    Furthermore, in this embodiment, by way of non-limiting example, the tower  100  is an off-shore tower, so that  FIGS. 1A ,  1 B,  1 C,  1 D and  3  illustrate a water surface line. 
         [0031]    More specifically, after providing said sections  2 ,  4 ,  6 ,  8 ,  10  in an initial position wherein said base section  10  is vertically disposed resting on said assembly surface  200  and said superimposed sections  2 ,  4 ,  6 ,  8  are disposed coaxially within said base section  10 , after providing assembly means  14 ,  16 ,  18  capable of selectively lifting said superimposed sections  2 ,  4 ,  6 ,  8 , and after providing operator support means  20  on the external surface of said base section  10  essentially vertically in correspondence with the upper edge of said base section  10 , all as shown in  FIG. 1A  and in the detail of  FIG. 3 , said superimposed sections  2 ,  4 ,  6 ,  8  are lifted. 
         [0032]    In this embodiment, wherein the tower  100  is an off-shore tower, it is preferred that said operator support means  20  are disposed above the maximum sea level foreseen. 
         [0033]    In accordance with the process of the present invention, the upper superimposed section  2  is first lifted followed by the superimposed section  4 . 
         [0034]    Specifically,  FIG. 1B  shows a stage in the process in accordance with this embodiment of the present invention wherein the upper superimposed section  2  has been totally lifted and immobilized to al superimposed section  4 , the superimposed section  4  has been totally lifted, and has formed a joint between the lower end portion of said superimposed section  4  and the upper end portion of the superimposed section  6 , radially external and immediately adjacent in relation to said superimposed section  4 , said joint being positioned essentially vertically in correspondence with said operator support means  20 . 
         [0035]      FIG. 1C  shows a later stage in the process in accordance with this embodiment of the present invention wherein the upper superimposed section  2  has been totally lifted and immobilized to the superimposed section  4 , the superimposed section  4  has been totally lifted and immobilized to the superimposed section  6 , the superimposed section  6  has been totally lifted, and a joint has been formed between the lower end portion of said superimposed section  6  and the upper end portion of the superimposed section  8 , radially external and immediately adjacent in relation to said superimposed section  6 , said joint being situated essentially vertically in correspondence with said operator support means  20 . 
         [0036]    Finally, the  FIG. 1D  shows a later stage of the process in accordance with this embodiment of the present invention wherein all the superimposed sections  2 ,  4 ,  6 ,  8  have been totally lifted and immobilized to the external and immediately adjacent section,  4 ,  6 ,  8 ,  10  respectively, the support means  400  of sections remaining empty. This process in accordance with an embodiment of the present invention includes an additional step of removing the operator support means  20 , and may still include a further additional step of removing the support means  400  of sections and/or an additional step of removing the assembly means  14 ,  16 ,  18 . 
         [0037]    As can be seen in  FIG. 3 , in this embodiment said assembly means include, for each superimposed section  2 ,  4 ,  6 ,  8 : two cables  16  which connect the lower end portion of each of said superimposed sections  2 ,  4 ,  6 ,  8  and the upper end portion of the radially external and immediately adjacent section,  4 ,  6 ,  8 ,  10  respectively; limiter means  18 , in this embodiment a wedge and stop plate set containing the wedge, disposed in the lower end of each cable  16 , to fix each of said cables  16  to each lower end portion; and traction means  14 , in this embodiment a jack fixed in the upper end of each cable  16 , to pull upward each cable  16  and this, in turn, each lower end portion. Said traction means  14  may comprise a plurality of jacks each installed in the upper end of each cable  16  (as shown) or may comprise a smaller number of jacks than cables, the available jacks being successively installed in the upper end of each cable  16 . The basic concept of these means  14 ,  16 ,  18  is known in the state of the art, for example through said document WO 2011/006526 A1, and shall not be explained here in greater detail. 
         [0038]    With reference now to  FIGS. 2A ,  2 B,  2 C,  2 D and  4 , the same telescopic tower  100  is illustrated that now implements a second embodiment of the process in accordance with the present invention. Said telescopic tower  100  thus comprises a foundation with an upper assembly surface  200 , a base section  10  and four superimposed sections  2 ,  4 ,  6 ,  8 , a wind turbine  300  and a support structure  400  of sections internally fastened to said base section  10 . 
         [0039]    In this embodiment, the intermediate superimposed sections  4 ,  6 ,  8  all have the form of a straight cylinder and the same length, the upper superimposed section  2  also has the form of a straight cylinder but has a length greater than that of the intermediate superimposed sections  4 ,  6 ,  8 , and the base section  10  has a truncated cone shape in a main lower portion and the form of a straight cylinder in the remaining portion, the total length of said base section  10  being larger than the length of said upper superimposed section  2 . 
         [0040]    Furthermore, in this embodiment, by way of non-limiting example, the tower  100  is an off-shore tower, so that  FIGS. 2A ,  2 B,  2 C,  2 D and  4  illustrate a water surface line. 
         [0041]    More specifically, after providing said sections  2 ,  4 ,  6 ,  8 ,  10  in an initial position wherein said base section  10  is vertically disposed resting on said assembly surface  200  and said superimposed sections  2 ,  4 ,  6 ,  8  are disposed coaxially within said base section  10 , after providing assembly means  14 ,  16 ,  18  capable of selectively lifting said superimposed sections  2 ,  4 ,  6 ,  8 , after providing operator support means  20  on the external surface of said base section  10  essentially vertically in correspondence with the upper edge of said base section  10 , and after providing guide means  22 ,  24 ,  26  on the external surface of said base section  10 , all as shown in  FIG. 2A  and in the detail of  FIG. 4 , said superimposed sections  2 ,  4 ,  6 ,  8  are lifted. 
         [0042]    In this embodiment wherein the tower  100  is an off-shore tower, it is preferred that said operator support means  20  are disposed above the maximum sea level foreseen. 
         [0043]    In accordance with the process of the present invention, the upper superimposed section  2  is first lifted followed by the superimposed section  4 . 
         [0044]    Specifically,  FIG. 2B  shows a stage of the process in accordance with this embodiment of the present invention wherein the upper superimposed section  2  has been totally lifted and immobilized to the superimposed section  4 , the superimposed section  4  has been totally lifted, and a joint has been formed between the lower end portion of said superimposed section  4  and the upper end portion of the superimposed section  6 , radially external and immediately adjacent in relation to said superimposed section  4 , said joint being situated essentially vertically in correspondence with said operator support means  20 . 
         [0045]      FIG. 2C  shows a later stage of the process in accordance with this embodiment of the present invention wherein the upper superimposed section  2  has been totally lifted and immobilized to the superimposed section  4 , the superimposed section  4  has been totally lifted and immobilized to the superimposed section  6 , the superimposed section  6  has been totally lifted, and a joint has been formed between the lower end portion of said superimposed section  6  and the upper end portion of the superimposed section  8 , radially external and immediately adjacent in relation to said superimposed section  6 , said joint being situated essentially vertically in correspondence with said operator support means  20 . 
         [0046]    Finally,  FIG. 2D  shows a later stage of the process in accordance with this embodiment of the present invention wherein all the superimposed sections  2 ,  4 ,  6 ,  8  have been totally lifted and immobilized to the external and immediately adjacent section,  4 ,  6 ,  8 ,  10  respectively, the support means  400  of sections remaining empty. This process in accordance with an embodiment of the present invention includes an additional step of removing the operator support means  20 , and may still include a further additional step of removing the support means  400  of sections and/or an additional step of removing the assembly means  14 ,  16 ,  18 . 
         [0047]    As can be seen in  FIG. 4 , said assembly means include, for each superimposed section  2 ,  4 ,  6 ,  8 : two cables  16  which connect the lower end portion of each of said superimposed sections  2 ,  4 ,  6 ,  8  and the upper end portion of the radially external and immediately adjacent section,  4 ,  6 ,  8 ,  10  respectively; limiter means  18 , in this embodiment a wedge disposed in the lower end of the cable  16  and a stop plate containing the wedge, to fix each of said cables  16  to each lower end portion; and traction means  14 , in this embodiment a jack fixed in the upper end of each cable  16 , to pull upward each cable  16  and this, in turn, each lower end portion. Said traction means  14  may comprise a plurality of jacks each installed in the upper end of each cable  16  (as shown) or may comprise a smaller number of jacks than cables, the available jacks being successively installed in the upper end of each cable  16 . The basic concept of these means  14 ,  16 ,  18  is known in the state of the art, for example through said document WO 2011/006526 A1, and shall not be explained here in greater detail. 
         [0048]    As can also be seen in  FIG. 4 , said guide means include: two fixing members  22 , in this embodiment lattice girders disposed vertically, situated in diametrically opposite positions, fixed by a lower portion to the external surface of said base section ( 10 ) so that it extends upward beyond the upper edge of said base section  10 ; two tensioning members  24 , in this embodiment rods disposed horizontally, which each emerge from each one of said girders  22  in a position above the upper edge of said base section  10 ; and two displacement elements  26 , in this embodiment wheels, each disposed at the free end of each of said rods  24 . Said rods  24  are disposed to press said wheels  26  against the superimposed section  2 ,  4 ,  6 ,  8  which is being lifted at any given time, and to guide the section in question throughout the desired trajectory. 
         [0049]    In the event that the guide means are formed by discrete structures identical or technically equivalent to the discrete structures  22 ,  24 ,  26  of this embodiment, preferably at least three of said structures will be provided and preferably said structures will be distributed equidistantly along the circumference of the base section of the tower. 
         [0050]    Naturally, maintaining the principle of the present invention, the embodiments and construction details may largely vary from those described and illustrated purely by way of non-limiting example, without, due to this, departing from the scope of the present invention as defined in the attached claims. 
         [0051]    In particular, by way of non-limiting illustration, although the preceding description has been made in relation to a telescopic tower which supports a wind turbine, the process in accordance with the present invention is not limited to this type of towers. 
         [0052]    Likewise, by way of non-limiting illustration, although the preceding description has been made in relation to a telescopic tower that rests on an assembly surface of a foundation, the process in accordance with the present invention is not limited to towers that rest on a foundation. 
         [0053]    Also by way of non-limiting illustration, although the preceding description has been made in relation to a telescopic tower comprising support means of sections that maintain the sections in initial position at a certain distance from the assembly surface, in the process in accordance with the present invention the sections, or part of them, in initial position may directly rest on the assembly surface. In the embodiments described above, said limiter means  18  (wedge disposed in the cable  16  and stop plate containing the wedge) could therefore be disposed in the upper end of each cable  16 , and said traction means  14  (jack fixed at the end of the cable  16 ) could therefore be disposed in the lower end of each cable  16 . Nevertheless, according to the process in accordance with the present invention, in the embodiments described above the assembly of said traction means  14  or any other technically equivalent means are preferred in the upper end of said cables  16 , to enable that the operators housed in the operator support means  20  have direct access to said traction means  14 . 
         [0054]    Finally, also by way of non-limiting illustration, although the preceding description has been made in relation to a telescopic tower comprising assembly means including cables and jacks, the process in accordance with the present invention is not limited to this type of towers. For example, the assembly means may include push jack means that rest on the assembly surface and simply push each superimposed section according to the process of the present invention, or the assembly means may include a rack turret in the centre of the tower and at least one pinion that moves throughout the corresponding racks of the rack turret and simply pushes each superimposed section according to the process of the present invention.