Wind turbine tower and transport method

Abstract

The invention relates to a wind turbine tower and transport method. The tower sections (1, 4, 5) are stacked where the towers are manufactured. The first tower section (5) is placed upright using a crane (6) and a flange thereof is screwed to a lower attachment (10). A new tower section (4) is added and screwed onto the attachment (10), which, being stepped, leaves the tower sections (1, 4, 5) at different heights. The operation is repeated in this way until all the sections have been completed. An upper attachment (11) is then attached by screwing. Using cables (9) directly secured to the attachments (10 and 11), the assembly is tipped over to leave the nested tower (7) in a horizontal position ready for transport.

Description

File of the Invention The present invention describes a wind turbine tower, assembled by means of a selfhoisting system that inserts tower sections from the bottom. Said tower comprises a series of tower sections that are transported to the assembly site nested one inside the other, forming a nested tower. Background of the Invention The known state of the art covers various fastening solutions for towers to enable their transport in a nested configuration. Among the existing patent documents, the following stand out: Patent CN105804952A discloses tower sections inserted into one another and transported horizontally, which are secured to each other by a plate at the bottom and with connecting pieces at the top. The connections are made using profiled bolts, and guide wheels are provided between the towers to allow them to slide relative to one another. Patent CN108167126A discloses a telescopic tower that uses locking elements to keep the nested towers extended. The locking element is a bushing subjected to a pushing force. It also incorporates guide rails on the outer tower section, along which existing blocks on the periphery of the inner tower section travel. Patent CN116816611A discloses several nested tower sections incorporating fastening devices 1, internal guides 2, floor supports 3, and lifting slings 4 and 5. The fastening with the fastening elements is achieved using bolts through the flanges of the tower sections. The internal guides for sliding tower sections are formed by wheels. Utility model CN219176494U discloses nested towers having protective elements between the tower sections to prevent damage during transport. The nested tower rests on grooved supports that connect with tabs on the outer tower section. The protective element is formed by several rings with a protective cover and a pair of support pads. No nested tower with the features of this new invention is known in the state of the art. The method of nesting the tower sections, as well as their handling before and after transport, also differs entirely from known methods, utilizing specific tooling that allows the nested tower to be turned over quickly and easily. Description of the Invention The tower object of the invention is a tower formed by several frustoconical sections. As these are tower sections that are self-erecting by being supported on strut columns and radial beams, the tower sections feature a double flange or an outer lip at their base, which serves as a support. The elements supporting the tower sections, the strut columns and radial beams, rest on said outer lip and are arranged in a triangular configuration that moves up and down between the columns of the self-erection system, allowing new tower sections to be inserted from below. It is an object of the invention that the tower sections be frustoconical so that they can be inserted one inside the other, since this would not be possible with a cylindrical configuration. It is another object of the invention that the outer lip of the double flange be provided with holes to facilitate its fixing in a vertical position onto the corresponding tooling. Another object of the invention is that the tooling, upon which the tower sections are nested while being bolted to the crossmembers of their supports, can be turned over, passing quickly and easily from a vertical position to a horizontal position. A further object of the invention is the provision of lower tooling and upper tooling, ang that both have stepped crossmembers. The method for stacking the tower sections is as follows: At the tower manufacturing site, the first tower section is is placed upright with a crane and bolted to the lower tooling. A new tower section is added and bolted onto the tooling, which being stepped, leaves the tower sections at different heights. This process is repeated in this manner until all sections are completed. The upper tooling is turned over to leave the nested tower in a horizontal position ready for transport. The following advantages arise from the description above: The tower is very lightweight and cost-effective due to having larger-than-standard diameters. The top section comes with its internals pre-installed at the factory to save on-site assembly time and facilitate the bolting of the upper tooling. For the remaining sections, the internals to be added later are pre-designed and pre-calculated. Transport can involve four, three, or even two tower sections, depending on weight limitations. For instance, road transport limits are 80 tonnes and 18 meters in length. Brief description of the drawings A brief description will be given below for a series of drawings useful for better understanding the invention and that expressly relate to an embodiment of said invention that is presented as a non-limiting example thereof. Figure 1 shows the tower with its characteristic flanges and double flanges, along with sectional details of the same. Figure 2 illustrates the tower nesting process, its rotation, and its storage for transport. Figure 3 presents specific details of the tower rotation using cables and winches. Figure 4 shows the clamping tooling and a stepped section thereof. Figure 5 shows a view of the lower tooling and its coupling with the nested tower. Figure 6 shows the other clamping tooling used and a section thereof. Figure 7 shows a view of the upper tooling and its coupling with the nested tower. Figure 8 presents a second embodiment of a tower without a double flange or outer lip, showing the corresponding section and a three-dimensional view of the lower tooling. Figure 9 shows a three-dimensional view of the nested tower and its tooling. Detail description The tower according to the invention is assembled using a self-erecting system that inserts tower sections from the bottom. The elements supporting the tower sections comprise strut columns and radial beams arranged in a triangular configuration that moves up and down between the columns of the self-erecting system. The connection between the strut columns and the radial beams is achieved via the outer lips present on the tower sections. As shown in Figure 1, the tower comprises: - a lower section (1) having an inner flange (2) which, in this section, coincides with the connection flange to the foundation, and an outer lip (3) that, in this case, will also be joined to the foundation, - several intermediate sections (4) with an inner flange (2) and an outer lip (3), and - an upper section (5) with an inner flange (2) and an outer lip (3). The tower sections (1, 4, and 5) are all of the same length and are frustoconical; however, they differ in that some have an inner flange (2) at both ends, while others feature a double flange or an outer lip (3) at the lower end. The tower sections are joined using bolts and nuts that pass through the inner flanges (2) of adjacent sections. The top section (5) connects its inner flange (2) to the wind turbine nacelle. The outer lipss (3) are provided with drilled holes. Figure 2 shows how the various tower sections (1, 4, and 5) are stored at the manufacturing site. Using a crane (6), the first tower section is raised to a vertical position and bolted to a tooling (not shown). A new tower section is added and bolted onto the tooling. This process is repeated until all sections are assembled, forming a unit known as a nested tower (7). The nested tower (7) is then turned to a horizontal position, ready to be loaded into the corresponding containers (8) for transport. The turning operation is performed using cables (9). Figure 3 shows, in detail, the nested tower (7) in a vertical position, bolted onto the lower tooling (10) and covered by the upper tooling (11). A cable (9) extends to the center of the upper tooling (11), and another cable (9) extends to one end of the lower tooling (10). By tensioning both cables (9), the nested tower (7) is positioned horizontally onto the base supports (12) provided on both toolings (10 and 11). Figure 4 shows the lower tooling (10). It comprises of a base support (12) from which respective tower supports (13) extend perpendicularly; these supports connect to the flanges of the tower sections via stepped crossmembers (14). In the lower tooling (10), both the upper and lower crossmembers (14) are stepped towards the exterior of the nested tower (7). These crossmembers (14) feature a number of steps corresponding to the number of tower sections, and they are preferably fastened using nuts and bolts. In the sectional detail shown in Figure 4, the lower tower (1) connects to the lower tooling assembly (10) at the base (15) of the crossbar, the intermediate tower section (4) connects at the first step (16), and the next tower section (4) connects at the second step (17). The gaps between the tower sections and the steps of the crossmembers (14) are wide enough to allow access for tightening the nuts and bolts used to fasten the tooling (10) to the nested tower (7). The base (15) of the crossbar corresponds to the smallest tower section, while the first step (16) and second step (17) correspond to the larger sections, as shown in Figure 5. The nuts and bolts of the crossmembers (14) are fastened through the holes in the outer lips (3) of the tower sections. Figure 6 shows the upper tooling (11). It also comprises of a base support (12) from which respective tower supports (13) extend perpendicularly; these are connected to the flanges of the tower sections by stepped crossmembers (14). The steps are oriented towards the interior of the nested tower (7), and the crossmembers are fastened to the tower sections using bolts and nuts. In the sectional detail of Figure 6, the upper tower section (5) connects to the upper tooling (11) at the inner side (18) of the crossmember (14). The next tower section (4) connects to the first step (19) of the crossmember (14), and the subsequent tower section (4) connects to the second step (20) of the crossbar. Thus, there are steps for each tower section. To secure the upper tooling (11), the latter features access holes (21) that allow manual access for nuts and bolts to the area otherwise obstructed by the tooling and the tower sections, as shown in Figure 7. In a second embodiment, the flanges of all tower sections are simple section-to-section contact flanges, without an outer lip. The nesting of the sections is carried out using a lower tooling stepped outwards, but by bolting the lower tooling (10) and the tower sections at their inner flange (2), according to the following method: - The lower tooling (10) is placed on the ground on the base support (12) and on two tower supports (13) that are parallel to each other, - a tower section (1) having an inner flange (2) is positioned vertically, - it is bolted to the base (15) of the crossmember (14) extending between the tower supports (13), - the second tower section is positioned vertically and its inner flange (2) is bolted to the first step (16), - the process is repeated with the third tower section, and its inner flange (2) is bolted to the third step (17), - the upper tooling (11) is placed over the nested tower sections, which form an internal stepped arrangement. In this case, local access holes (21) would also be required in the upper tooling (11) to allow access for installing the bolts. All of this is as shown in Figure 8. The general method for nesting the tower for transport is as follows: The tower sections are manufactured and stored. The upper section (5) has its internal components already installed: platform and ladder. The lower tooling (10) is placed on the ground atop the base support (12) and the two tower supports (13), which are parallel to each other. Using an auxiliary crane (6), the lower tower section (1), which may feature either an inner flange (2) alone or a double flange with an outer lip (3), is raised to a vertical position and bolted to the base (15) of the crossmember (14). The second tower section, an intermediate section (4) featuring an inner flange (2) or a double flange with an outer lip (3), is raised to a vertical position and bolted to the first step (16). The third tower section is raised to a vertical position and bolted to the second step (17). This operation is repeated for as many tower sections as are to be nested. The upper tooling (11) is placed over the nested tower sections, which form an internal stepped arrangement. The platform of the upper tower section, which comes preassembled from the factory, can be used for this purpose. The local access holes (21) 5 in the upper tooling (11) are highly useful for manually handling nuts and bolts in the area enclosed by the tooling and the tower sections. As shown in Figure 9, the nested tower (7) is moved from a vertical to a horizontal position, resting on the base supports (12) provided on both toolings (10 and 11). It is thus positioned for loading into the corresponding containers (8) for transport.

Claims

CALIMS1- Wind turbine tower formed by several tower sections having a frustoconical shape, characterized in that the tower sections (1, 4, 5) all have an inner flange (2) and may have an outer lip (3); said sections (1, 4, and 5) have the same height, and at least two sections are inserted vertically one inside the other and secured in a stepped manner using a lower tooling (10) resting on the ground and an upper tooling (11) that closes the assembly, by bolting their stepped crossmember (14) to the inner flanges (2) and to the outer lips (3), if present, leaving the nested tower (7) ready for turning over and transport.2- Wind turbine tower according to the preceding claim, characterized in that the tooling (10 and 11) are formed by a base support (12) from which respective tower supports (13) extend perpendicularly, connected to the tower sections by stepped crossmembers (14), wherein the crossmembers of the lower tooling (10) are stepped towards the exterior of the nested tower (7) and the crossmembers of the upper tooling (11) are stepped towards the interior of the nested tower (7).3- Wind turbine tower according to claim 1, characterized in that a cable (9) extends to the center of the upper tooling (11) and another cable (9) extends to one end of the lower tooling (10).4- Wind turbine tower according to claim 1, characterized in that the stepped crossmember (14) of the upper tooling (11) features local access holes (21) for manual access of nuts and bolts to an area occluded by the tooling and the tower sections.5- Wind turbine tower according to claim 1, characterized in that the upper section (5) already has a platform and a ladder section mounted thereon, and the remaining sections have interfaces allowing for the on-site mounting of their platforms and ladder sections after the sections have been de-nested.6- Wind turbine tower according to claim 1, characterized in that the tower sections (1, 4, 5) have a double flange with an outer lip (3), and said outer lip (3) is drilled with holes to receive the nuts and bolts that are fastened to the crossmembers (14).7- Method for transporting a wind turbine tower formed by several previouslymanufactured and stored frustoconical sections, characterized in that:- a lower tooling (10) is placed on the ground upon a base support (12) and upon two tower supports (13) that are parallel to each other,- a lower tower section (1), which has an inner flange (2) and may have a double flange with an outer lip (3), is placed in a vertical position,- it is bolted to a base (15) of a crossmember (14) stepped outwardly, which extends between the tower supports (13),- the second tower section, which is an intermediate section (4) with an inner flange (2) and may have a double flange with an outer lip (3), is placed in a vertical position and bolted to the first step (16),- the third tower section is placed in a vertical position and bolted to a second step (17),- the process is repeated for as many tower sections as are to be nested,- the upper tooling (11), with its crossmember (14) stepped inwardly and having local access holes (21), is placed over the nested tower sections,- leaving each tower section of the nested tower assembly (7) at a different height.8- The transport method according to claim 7, wherein the flanges of the tower sections all have a double flange with an outer lip (3), characterized in that:- the lower tooling (10) is placed on the ground upon the base support (12) and upon two tower supports (13) that are parallel to each other,- a tower section (1) having a double flange with an outer lip (3), drilled with holes to receive the nuts and bolts that are fastened to the crossmember (14), is placed in a vertical position,- it is bolted to the base (15) of the crossmember (14) extending between the tower supports (13),- the second tower section is placed in a vertical position and its double flange with an outer lip (3) is bolted to the first step (16),- the process is repeated for as many tower sections as are to be nested,- the upper tooling (11) is placed over the nested tower sections, which form an internal stepped arrangement.9- The transport method according to claim 7, characterized in that a cable (9) extends to the center of the upper tooling (11) and another cable (9) to an end of the lower tooling (10); by tensioning both cables (9), the nested tower (7) is turned over, moving from the vertical position to a horizontal position and resting on the base supports (12) that both toolings (10 and 11); and finally, the nested tower (7) is left ready to be inserted into its corresponding containers (8) for transport.

Images