Tower and mold

Abstract

A tower (6) obtainable by a method for manufacturing a tower (6) comprising at least two annular concrete sections (8), the method comprising the following steps: Providing a casting mold, the inner surface of the casting mold having a first arcuate surface (13') and a second arcuate surface (14') facing the first arcuate surface (13'), Machining the first arcuate surface (13') and the second arcuate surface (14') of the mold, horizontal casting of a segment of a cylindrical or frustoconical pipe (12) by filling the mould with concrete, Hardening of the concrete and Stacking at least two annular concrete sections (8) on top of each other, wherein at least one of the annular concrete sections (8) consists of at least two of the horizontally cast segments of a cylindrical or frustoconical tube (12), wherein the at least one annular concrete section (8) abuts the other annular concrete section (8) with its first arcuate surfaces (13) or its second arcuate surfaces (14), thereby forming a horizontal dry joint, wherein the casting mold is segmented such that the first arcuate surface (13') and / or the second arcuate surface (14') is separable into at least two parts, wherein the first arcuate surface (13') and / or the second arcuate surface (14') is preferably divided radially into the at least two parts, wherein the at least two parts of the first arcuate surface (13') are machined separately and / or the at least two parts of the second arcuate surface (14') are machined separately.

Description

FIELD OF THE INVENTIONThis invention relates to a tower which can be obtained by a method of making a tower, the combination of machining certain surfaces of a mould and the horizontal casting of concrete segments in the mould allowing the construction of towers with dry horizontal impacts. Moreover, this invention relates to a mould designed to enhance the advantages of the innovative method for the tower.BACKGROUNDExisting methods for constructing towers used to support various types of equipment such as antennas, mobile telephone equipment or wind turbine equipment vary depending on whether the tower materials are steel or concrete. The decision process as to whether to construct the tower from steel or concrete may depend on the geographical location, regional resources, requirements for tower height and load carrying capacity, and access to the site for the construction of the tower. Steel towers are usually constructed by bolting steel pipe sections together at intermediate flanges. Generally, as a tower increases in height, the diameter of the tower base increases to accommodate higher loads generated by the higher tower. The height of steel towers is often limited by the diameter of the steel pipe sections that can be physically transported to the worksite without requiring substantial changes to existing roads, bridges, or other road constraints. Transporting large diameter steel pipe sections and associated components also increases the cost of tower construction.Concrete towers have advantages over steel towers because they can be manufactured at or near the tower location when the construction materials are available on site. In on-site casting processes, concrete is poured into moulds erected at the tower site. Disadvantages of on-site casting processes include lower build speed and susceptibility to bad weather. In addition, the shape of a typical concrete wind turret is often at least partially tapered, which complicates the concreting process. Alternatively, concrete tower sections may be made or precast and then stacked on site to form the tower. Joints between tower segments typically require mortars to ensure sufficiently strong joints, and mortars may be required to be pumped at tower heights of up to 300 feet or more, which is time consuming, requires special equipment and is weather dependent, thereby increasing tower construction costs.Although making towers using precast segments offers efficiency advantages, mortar in horizontal joints is a significant drawback to this approach.Against this background, DE 10 2008 016828 A1 describes a production process in which concrete is poured into a casting mold with a flat base in order to realize a flat underside. After the concrete has reached a predetermined minimum strength, a compensating layer is applied to a joint surface of the prefabricated concrete part opposite the underside. As soon as the compensating layer has reached a predetermined minimum strength, the prefabricated concrete part is arranged on an exactly horizontally oriented surface and the compensating layer is plane-parallel ablated on the upper side.This method produces planar surfaces which make it possible to eliminate the time-consuming and cost-intensive provision in the horizontal joints. However, this procedure requires two complicated additional method steps, namely the application of a compensating layer and the processing of the compensating layer.Furthermore, WO 2011 / 157659 A1 describes a method for producing a tower of a wind turbine, wherein at least one tubular tower section is produced from ring-shaped prefabricated concrete parts with two horizontal contact surfaces which are arranged one above the other. After casting, the ring-shaped prefabricated concrete parts are set up in a machining station in the factory and the two horizontal contact surfaces of the prefabricated concrete parts are machined plane-parallel and in a material-removing manner in a clamping device.This approach also has the disadvantage that each annular prefabricated concrete part has to be machined on its horizontal contact surface.Moreover, WO 2020 / 208046 A2 describes, in the remote technical field of manufacturing emphasis carriages for a tunnel excavation system, a manufacturing process which is fundamentally different from the established vertical casting of concrete segments for towers in that the casting is performed horizontally.SUMMARY OF THE INVENTIONIn view of the foregoing, it is therefore an object of the present invention to provide a tower obtained by a manufacturing process that facilitates the cost and time efficient construction of towers, and a casting mold that enhances the advantages of the innovative manufacturing process.This object is achieved by the claimed subject matter as defined in the appended claims.Recent developments have shown that providing ring-shaped concrete sections with a very precise surface planarity allows to stack the ring-shaped concrete sections directly with dry horizontal joints, i.e. without having to apply additional adhesive agents such as mortars, jointing mortars or adhesive agents in the horizontal joints. However, sufficiently planar surfaces have previously required additional, complicated manufacturing steps such as machining the concrete surfaces, which partially cancels the advantageous effects of using dry impacts.In view of this, the present inventors found that concrete casting generally results in inferior surface qualities on the top surface of the casting. An explanation of this phenomenon is the lack of a positive gravitational effect, i.e. the pressure which the casting compound exerts on the lower and side surfaces of the casting element, on the upper side. In addition, bubbles formed during the curing process increase upward and further degrade the surface quality on the upper surface.Based thereon, the inventors have developed a new manufacturing process for concrete towers based on a horizontal casting process. This process makes use of the finding that, in a horizontal casting process, the future horizontal contact surfaces of the casting elements are located on one side of the casting mold. In other words, the future horizontal contact surfaces of the cast elements are not affected by the aforementioned adverse effects occurring during casting on the top side.The inventors have additionally surprisingly found that the horizontal production processes for producing concrete segments in the remote technical field of tunnel construction are also fundamentally suitable for producing towers. While the superior surface quality at the side surfaces of the casting mold plays no part in connection with tunnel production, the underlying established processes have proven to be a reliable master for the design of a production process for a horizontal tower.However, despite the improved surface quality of the future horizontal contact surfaces of the cast elements achieved by the horizontal casting process, the surface tolerance levels determined by the present inventors were not yet sufficient for the intended dry impacts. Surprisingly, the inventors found that machining at least the mold surfaces that are in contact with the future horizontal contact surfaces of the cast elements significantly improved the final surface qualities of the future horizontal contact surfaces.In summary, the inventors therefore surprisingly found that the combination of machining certain surfaces of a casting mould and the horizontal casting of concrete segments in this casting mould leads to considerably improved surface qualities, which ultimately enables the production of a concrete tower with dry horizontal impacts.According to the inventive manufacturing method, a mold is provided whose inner surface has a first arcuate surface and a second arcuate surface facing the first arcuate surface. The first arcuate surface and the second arcuate surface are flat. The first and second arcuate surfaces will result in corresponding surfaces in the cast pipe segment which may represent future horizontal contact surfaces of the annular concrete sections. Subsequently, the first arcuate surface and the second arcuate surface of the casting mold are machined and a segment of a cylindrical or frusto-conical tube is cast horizontally by filling the casting mold with concrete. In the context of the present invention, "horizontally cast" means that casting is performed while the axis of the pipe segment is oriented in a substantially horizontal direction. The axis of the pipe segment corresponds to the central axis of the pipe.After casting, the concrete is cured and at least one annular concrete section is formed from at least two of the horizontally cast segments of a cylindrical or frusto-conical tube. Subsequently, at least two annular concrete sections are stacked on top of each other, wherein at least one of the annular concrete sections is formed from the at least two horizontally cast pipe segments. The stacking is performed such that the at least one annular concrete section, which consists of two or more pipe segments, abuts with the first arcuate surfaces or the second arcuate surfaces of its pipe segments against the other annular concrete section and thereby forms a dry abutment. A dry joint is a joint free of adhesive agents such as mortar, mortar or adhesive.The processing of the first arcuate surface and the second arcuate surface preferably precedes the provision of the casting mold.According to a preferred embodiment of the invention, the casting mold is segmented such that the first arcuate surface and / or the second arcuate surface is separable into at least two parts. Preferably, the first arcuate surface and / or the second arcuate surface is radially divided into the at least two parts. In this embodiment, the at least two portions of the first and / or second arcuate surfaces are separately machined. In the context of the present invention, "radially divided" means that the arcuate surface is divided by a radial cut line.On the one hand, it is generally preferable to assemble annular concrete sections from as few pipe segments as possible, thereby reducing the number of vertical connections between the pipe segments. On the other hand, some towers require large diameters for sufficient structural stability, especially for wind turbine towers of high height. At least some of the pipe segments of a tower therefore have a considerable radial length, which among other things exceeds the conventional radial lengths of pipe segments in tunnel manufacturing processes. This size presents a severe machining challenge, which can be preferably performed with 5-axis CNC milling machines. Surprisingly, the inventors of the present invention have found that the separate processing of the first and / or second arcuate surfaces and the subsequent re-combining of the segmented parts still yields satisfactory surface qualities on the future horizontal contact surfaces of the cast elements.Preferably, the at least two parts of the first arcuate surface and / or the second arcuate surface are configured to be separately openable. Thus, the at least two parts may be opened separately before removing the horizontally cast cylindrical or frusto-conical tube segments. This facilitates removal of the cast tube segment from the casting mold.According to a further preferred embodiment of the invention, a separable part of the first or second arcuate surface has a groove and the other separable part of the first or second arcuate surface has a protrusion, wherein the protrusion of the one separable part is formed such that it engages in the groove of the other separable part in a closed state of the casting mold. The groove-protrusion arrangement facilitates the accurate positioning of the separated portions of the first and / or second arcuate surfaces of the mold.Segments of cylindrical or frusto-conical tube are preferably longitudinally cut segments of cylindrical or frusto-conical tube. Longitudinally sectioned means segmented along a line parallel to the longitudinal axis of the pipe segment, i.e., the central axis of the pipe.According to a preferred embodiment of the invention, the annular concrete section comprising at least two of the horizontally cast segments of a cylindrical or frustoconical tube is initially pre-assembled by positioning and connecting the horizontally cast segments of a cylindrical or frustoconical tube so as to form an annular concrete section, and the annular concrete section is subsequently positioned on a foundation or another annular concrete section. Pre-assembling an annular concrete section prior to stacking on a foundation or other annular concrete section is far less complicated at a pre-assembly location than on a foundation or other annular concrete section, thereby greatly facilitating the overall process.Preferably, the annular concrete section comprises three horizontally cast segments of a cylindrical or frusto-conical tube. It has been found that three segments represent an excellent compromise between the efforts to reduce the number of vertical connections and the size constraints imposed by the necessary transport of the pipe sections from the manufacturing location to the construction site.The manufacturing process of the present invention is particularly advantageous for the construction of wind turbine towers.Preferably, the inner surface of the casting mold comprises a first wall surface and a second wall surface in the form of a longitudinally cut open cylindrical surface or open frustoconical surface, the first wall surface and the second wall surface being adjacent to the first arcuate surface and the second arcuate surface, respectively, and the first wall surface facing the second wall surface. Furthermore, the casting mold has a first lateral surface and a second lateral surface, wherein the first lateral surface and the second lateral surface are each adjacent to the first arcuate surface, the second arcuate surface, the first wall surface and the second wall surface.The method of manufacturing a tower is preferably performed by casting the at least two segments of cylindrical or frusto-conical tube at a manufacturing location and then transporting the resulting segments to the construction site of the tower. This approach represents an efficient use of the production means.The manufacturing process of the present invention yields a tower that can be constructed in a cost and time efficient manner.The mold of the present invention defines a cavity in the form of a segment of cylindrical or frusto-conical tube, the shape corresponding to a longitudinally cut segment of cylindrical or frusto-conical tube. The inner surface of the casting mold has a first arcuate surface and a second arcuate surface facing the first arcuate surface. The inner surface of the casting mold further includes a first wall surface and a second wall surface in the form of a longitudinally cut open cylindrical surface or open frustoconical surface, the first wall surface and the second wall surface being adjacent to the first arcuate surface and the second arcuate surface, respectively, and the first wall surface facing the second wall surface. The inner surface of the mold additionally includes a first side surface and a second side surface, the first side surface and the second side surface being adjacent to the first arcuate surface, the second arcuate surface, the first wall surface, and the second wall surface, respectively. The mold is segmented such that the first arcuate surface and / or the second arcuate surface are separable into at least two portions. As mentioned above, the inventors have surprisingly found that while the size of the first and / or second arcuate surfaces presents severe challenges for machining, separately machining the first and / or second arcuate surfaces and then re-combining the segmented parts still yields satisfactory surface qualities on the future horizontal contact surfaces of the cast elements. The casting mould is therefore capable of producing very large pipe segments with excellent surface qualities.Preferably, the first arcuate surface and / or the second arcuate surface of the casting mould is radially divided into the at least two parts.According to a preferred embodiment of the invention, the diameter of the annular concrete section is greater than the height of the annular concrete section, preferably 1.5, 2 or 3 times greater than the height of the annular concrete section.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 shows a wind turbine with a concrete tower according to an embodiment of the invention; FIG. 2 shows a situation during a method for manufacturing a concrete tower according to an embodiment of the invention; FIG. 3 shows a molded segment of a cylindrical tube according to an embodiment of the invention in an upright position. FIG. 4 shows a cast segment of a cylindrical tube according to an embodiment of the invention in a horizontal position.In the figures, like reference numerals designate like or functionally equivalent elements unless otherwise indicated.DESCRIPTION OF EMBODIMENTSHereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of the embodiments is for illustrative purposes only and is not to be taken in a limiting sense. It should be noted that the drawings are to be considered as schematic representations only, and elements in the drawings are not necessarily to scale with respect to one another. Rather, the representation of the various elements is chosen so that those skilled in the art will understand their function and general purpose. As used herein, the singular forms "a / r / s" and "the / s" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprise," "comprise," "have," and "include" are to be construed as open ended terms (i.e., having the meaning "including, but not limited to") unless otherwise indicated. Further, it is immediately clear that the shape of the cavity of the casting mold may correspond to the shape of the resulting cast product. Thus, within the scope of this invention, features describing the shape of the cavity of the casting mould may also describe the shape of the segment of a cylindrical or frusto-conical tube and vice versa.Fig. 1 shows a wind turbine 1 with a concrete tower according to an embodiment of the invention. In this embodiment, the wind turbine 1 comprises a rotor 2 with one or more rotor blades 3 connected to a hub 4. The hub 4 may be connected to a generator (not shown) disposed in a nacelle 5. During operation of the wind turbine 1, the rotor blades 3 are driven to rotate by wind and the kinetic energy of the wind is converted into electrical energy by the generator in the nacelle 5. The nacelle 5 may be arranged at the upper end of a tower 6 of the wind turbine 1. The tower 6 can be erected on a foundation 7, such as a monople or a concrete foundation. The foundation 7 may be connected to and / or driven into the ground or seabed.The tower 6 extends in a height direction H. The height direction H is a vertical direction of the tower 6 in the erected state.Although FIG. 1 does not show all individual annular concrete sections, the tower 6 comprises at least two annular concrete sections 8, but the tower 6 may also comprise more than two annular concrete sections, wherein the more than two tubular tower sections 8 divide the tower 6 in the height direction H.The tower 6 may be a concrete tower. In other examples, the tower 6 may also be a hybrid tower comprising annular concrete sections 8 in a lower portion thereof and a steel tower section (not shown) in an upper portion thereof.FIG. 2 shows the annular concrete sections 8 during an exemplary embodiment of the manufacturing method of the present invention, namely during stacking of the annular concrete sections 8, the annular concrete sections 8 consist of several horizontally cast segments of a cylindrical or frustoconical tube 12, the annular concrete sections 8 being raised and arranged on top of each other by means of a crane 11 (only partially shown). Fig. 2 shows an example in which each annular concrete section 8 consists of three horizontally cast segments 12.Figure 3 schematically shows a horizontally cast segment of a cylindrical or frusto-conical tube 12 according to a preferred embodiment of the invention in an upright, i.e. vertical, position. The segment 12 has a first arcuate surface 13 and a second arcuate surface 14 (not shown) facing the first arcuate surface 13. The segment 12 further includes a first wall surface 15 and a second wall surface 16 (not shown), each in the form of a longitudinally cut open cylindrical surface or open frustoconical surface. The first wall surface 15 and the second wall surface 16 are respectively adjacent to the first arcuate surface 13 and the second arcuate surface 14, and the first wall surface 15 faces the second wall surface 16. The segment 12 further includes a first side surface 17 and a second side surface 18. The first wall surface 17 and the second wall surface 18 are respectively adjacent to the first arcuate surface 13, the second arcuate surface 14, the first wall surface 15, and the second wall surface 16.FIG. 4 schematically shows the horizontally cast segment of FIG. 3 in the horizontal position, i.e. the position in which the segment is cast.List of reference characters1 Wind turbine 2 rotor 3 rotor blades 4 hub 5 nacelle 6 tower 7 foundation 8 annular concrete section 11 crane 12 segment of cylindrical or frusto-conical tube 12' mould cavity in the form of cylindrical or frusto-conical tube 13 first arcuate surface of the segment 13' first arcuate surface of the mould cavity 14 second arcuate surface of the segment 14' second arcuate surface of the mould cavity 15 first wall surface of the segment 15' first wall surface of the mould cavity 16 second wall surface of the segment 16' second wall surface of the mould cavity 17 first side surface of the segment 17' first side surface of the mould cavity 18 second side surface of the segment 18' second side surface of the mould cavity H height direction of the towerReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2008 016828 A1

[0005] WO 2011 / 157659 A1

[0007] WO 2020 / 208046 A2

[0009]

Claims

A tower (6) obtainable by a method of manufacturing a tower (6) comprising at least two annular concrete sections (8), the method comprising the steps of: providing a casting mould, the inner surface of the casting mould having a first arcuate surface (13') and a second arcuate surface (14') facing the first arcuate surface (13'), machining the first arcuate surface (13') and the second arcuate surface (14') of the casting mould, horizontally casting a segment of a cylindrical or frusto-conical tube (12) by filling the casting mould with concrete, hardening the concrete and stacking at least two annular concrete sections (8) on top of each other, wherein at least one of the annular concrete sections (8) consists of at least two of the horizontally cast segments of a cylindrical or frusto-conical tube (12), wherein the at least one annular concrete section (8) abuts with its first arcuate surfaces (13) or its second arcuate surfaces (14) against the other annular concrete section (8), thereby forming a horizontal dry impact, wherein the casting mold is segmented such that the first arcuate surface (13') and / or the second arcuate surface (14') is separable into at least two parts, wherein the first arcuate surface (13') and / or the second arcuate surface (14') is preferably radially divided into the at least two parts, wherein the at least two parts of the first arcuate surface (13') are processed separately and / or the at least two parts of the second arcuate surface (14') are processed separately.The tower (6) according to claim 1, wherein the at least two parts of the first arc-shaped surface (13') and / or the at least two parts of the second arc-shaped surface (13') are opened separately prior to removing the horizontally cast cylindrical or frusto-conical tube segments (12).Tower (6) according to claim 1 or 2, wherein a separable part of the first arcuate surface (13') has a groove and another separable part of the first arcuate surface (13') has a protrusion, and / or wherein a separable part of the second arcuate surface (14') has a groove and another separable part of the second arcuate surface (14') has a protrusion, wherein the protrusion of the one separable part is configured such that it engages in the groove of the other separable part in a closed state of the casting mould.Tower (6) according to any of the preceding claims, wherein the casting mould defines a cavity in the form of a longitudinally cut segment of a cylindrical or frustoconical tube (12').Tower (6) according to any of the preceding claims, wherein the annular concrete section (8) comprising at least two of the horizontally cast segments of a cylindrical or frustoconical tube (12) is initially pre-assembled by positioning and assembling the horizontally cast segments of a cylindrical or frustoconical tube (12) so as to form an annular concrete section (8), and the pre-assembled annular concrete section (8) is subsequently positioned on a foundation (7) or another annular concrete section (8).Tower (6) according to any of the preceding claims, wherein one of the annular concrete sections (8) is formed by joining three of the horizontally cast segments of a cylindrical or frusto-conical tube (12).Tower (6) according to any of the preceding claims, wherein the tower (6) is a wind turbine tower.The tower (6) according to any one of the preceding claims, wherein the inner surface of the casting mould further comprises: a first wall surface (15') and a second wall surface (16') in the form of a longitudinally cut open cylindrical surface or open frustoconical surface, the first wall surface (15') and the second wall surface (16') being adjacent to the first arcuate surface (13') and the second arcuate surface (14'), respectively, and the first wall surface (15') facing the second wall surface (16'), and a first side surface (17') and a second side surface (18'), the first side surface (17') and the second side surface (18') being adjacent to the first arcuate surface (13'), the second arcuate surface (14'), the first wall surface (15') and the second wall surface (16'), respectively.Tower (6) according to any of the preceding claims, wherein the casting of the at least two segments of a cylindrical or truncated cone shaped pipe (12) is performed at a manufacturing location and the resulting segments (12) are subsequently transported to the construction site of the tower (6).A mold defining a cavity in the form of a segment of a cylindrical or frusto-conical tube (12'), the mold corresponding to a longitudinally cut segment of a cylindrical or frusto-conical tube, the inner surface of the mold having: a first arcuate surface (13') and a second arcuate surface (14') facing the first arcuate surface (13'), a first wall surface (15') and a second wall surface (16') in the form of a longitudinally cut open cylindrical surface or open frusto-conical surface, the first wall surface (15') and the second wall surface (16') being adjacent to the first arcuate surface (13') and the second arcuate surface (14'), respectively, and the first wall surface (15') facing the second wall surface (16'), respectively, and a first side surface (17') and a second side surface (18'), wherein the first side surface (17') and the second side surface (18') are adjacent to the first arcuate surface (13'), the second arcuate surface (14'), the first wall surface (15') and the second wall surface (16'), respectively, wherein the casting mold is segmented such that the first arcuate surface (13') and / or the second arcuate surface (14') is separable into at least two parts.The mold of claim 10, wherein the first arcuate surface (13') and / or the second arcuate surface (14') is radially divided into the at least two parts.The mold according to claim 10 or 11, wherein the at least two parts of the first arcuate surface (13') and / or the second arcuate surface (14') are configured to be separately openable.The casting mold according to any one of claims 10 to 12, wherein a separable part of the first arcuate surface (13') has a groove and another separable part of the first arcuate surface (13') has a protrusion, and / or wherein a separable part of the second arcuate surface (14') has a groove and another separable part of the second arcuate surface (14') has a protrusion, wherein the protrusion of the one separable part is configured such that it engages in the groove of the other separable part in a closed state of the casting mold.

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