Wind turbine tower and method of production thereof

Abstract

A wind turbine tower is made of reinforced concrete with fiber rovings as reinforcements, wherein the fiber rovings are basalt fiber rovings. In one embodiment, the basalt fiber rovings may include, for example, a bundle of multiple parallel oriented basalt fibers forming a thin rope. In one embodiment, the tower is produced in a slip forming process or slip molding process, wherein the basalt fiber rovings are embedded in the concrete during the slip forming process.

Claims

1. A slip-formed wind turbine tower comprising, a reinforced concrete hollow structure with fibre rovings as reinforcements, wherein the fibre rovings are basalt fibre rovings, and wherein the basalt fibre rovings are embedded in the concrete during the slip forming process, wherein each of the basalt fibre rovings are embodied as a bundle of multiple parallel oriented basalt fibers, and wherein at a top portion of the tower, the tower adapts to a yaw-construction, and the basalt fibre rovings are placed in paths that deviate from the parallel path orientation found in a portion of the tower below the top portion in order to cope with the intensive tensions and stresses which act on this part of the tower.

2. The wind turbine tower according to claim 1, wherein the basalt fibre diameter is in the range of 5 m to 30 m; and/or the number of basalt fibers in the roving is between 500 and 2000 or is between 5000 and 30000; and/or the basalt fibre roving weight is between 0.20 and 30 kg/km.

3. The wind turbine tower according to claim 1, wherein the basalt fibre rovings are anchored in the concrete already at the bottom of the wind turbine tower and it ends at the top of the wind turbine tower.

4. The wind turbine tower according to claim 1, wherein at least some of the basalt fibre rovings are wound around the wind turbine tower in a first angle relative to the longitudinal axis of the tower.

5. The wind turbine tower according to claim 4, wherein said first angle is an angle of 25 degrees.

6. The wind turbine tower according to claim 1, wherein at least some of the basalt fibre rovings are wound around the wind turbine tower in a second angle relative to the longitudinal axis of the tower.

7. The wind turbine tower according to claim 6, wherein said second angle is 85 degrees, so that the basalt fibre rovings generally follow the circumference of the tower.

8. The wind turbine tower according claim 1, wherein at least some of the basalt fibre rovings are placed in the concrete in a zero degree angle relative to the longitudinal axis of the tower.

9. The wind turbine tower according claim 1, wherein the basalt fibre rovings are pre-tensioned when placed in the concrete during a slip moulding process in order not to create any wrinkles on the basalt fibre rovings or to stabilise the tower.

10. The wind turbine tower according to claim 1, wherein the basalt fibre rovings are configured to be embedded as a supplement to conventional iron bar reinforcement, or the conventional iron bar reinforcement is configured to be embedded as a supplement to the basalt fibre rovings.

11. The wind turbine tower according to claim 1, wherein as at least one basalt fibre roving approaches a top of the tower the roving deviates circumferentially from an angle with respect to a vertical axis of the tower that the roving maintains in a remainder of the tower.

12. The wind turbine tower according to claim 1, wherein the reinforced concrete is adapted to reach a height of 120 meters based on a configuration of the basalt fibre rovings.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features, properties and advantages will become clear from the following description of embodiments in conjunction with the accompanying drawing, wherein:

(2) FIG. 1: shows a schematic side view of a wind turbine tower with of the positions and directions in which the basalt fibre rovings will be positioned

DETAILED DESCRIPTION OF INVENTION

(3) FIG. 1 shows a schematic side view of a wind turbine tower 1 made of reinforced concrete 3.

(4) The reinforced concrete 3 of the a wind turbine tower 1 has fibre rovings 2,8,9,10 as reinforcements, wherein the fibre rovings are basalt fibre rovings.

(5) A basalt fibre roving may be manufactured from volcanic basalt rock. In an exemplary process of manufacture, basalt rock is mined and crushed to gravel size. The crushed basalt is fed into a special furnace for melting. Molten basalt from the furnace is drawn from a bushing. The bushing may be made, for example from platinum. The bushing generally has multiple orifices or tips, for example 200-800 tips, wherein each orifice or tip produces one filament. The drawn out filaments are then cooled, for example, by a mist of water, and sized. Subsequently, the filaments are wound onto a winder as a unit. For example, the filaments are not twisted together, but form a flattened bundle. The wound filaments are then dried, for example, in an oven and subsequently reprocessed into rovings.

(6) Basalt fibre has a tensile strength of about 4,840 Mpa and an elastic modulus of about 89 Gpa. Basalt fibers can be operated in a wide variety of temperatures, including a minimum application temperature of about 260 C (435 F), a maximum application temperature of about 980 C (1800 F) and a maximum sustained application temperature of 850 C (1560 F).

(7) The above described process of manufacture of basalt fibre rovings is exemplary. Basalt fibre rovings made via alternate manufacturing techniques may be also used in the production of the inventive wind turbine tower.

(8) In FIG. 1, the basalt fibre rovings 2,8,9,10 are shown in different positions and directions in which the basalt fibre rovings 2,8,9,10 can be positioned. The different positions and directions of the basalt fibre rovings 2,8,9,10 are shown as example and can be combined deliberately to create different optimized embodiments of the wind turbine tower 1. Alternatively, only one position and/or direction of the shown basalt fibre rovings 2,8,9,10 can be chosen for the whole wind turbine tower 1.

(9) The basalt fibre rovings 2,8,9,10 may be embodied as a bundle of multiple parallel oriented basalt fibers, with around 200 basalt fibers, forming a thin rope.

(10) The tower 1 is produced in a slip forming process or slip moulding process. Slip forming for construction is a method of continuously pouring concrete into a form of mould that moves up vertically, normally with the assistance of hydraulic or screw jacks. As the forming of the tower structure progress, the section of previously poured concrete hardens and forms a kind of support wall that is strong enough to withstand the concrete poured over the top of it. Pouring continues until the desired height of the structure is reached, allowing for a type of concrete structure that is positioned on top of a foundation and completely hollow inside. The basalt fibre rovings 2,8,9,10 will be embedded in the concrete 3 during the slip forming process.

(11) The basalt fibre rovings 2,8,9,10 can be anchored in the concrete 3 at the bottom 5 and at the top 4 of the wind turbine tower 1.

(12) Some basalt fibre rovings 2,8,9,10 are winded around the wind turbine tower 1 in a given angle , relative to the longitudinal (vertical) axis A of the wind turbine tower 1

(13) Some basalt fibre rovings 8 are in an angle of =25 degrees.

(14) Some basalt fibre rovings are in an angle of =85 degree so that they basically follow the circumference of the tower wind turbine tower 1.

(15) Some basalt fibre rovings 10 are placed in the concrete 3 in a zero degree angle relative to the longitudinal axis A of the tower 1, optionally under pretension.

(16) At the top 4 of the wind turbine tower 1, the tower 1 adapts to either a yaw-construction 11 or to some transition piece between the tower 1 and the yaw-construction 11.

(17) The basalt fibre rovings 12 are placed in paths in order to cope with the intensive tensions and stresses which act on this part of the tower 1.

(18) The basalt fibre rovings 2,8,9,10 are pre-tensioned when placed in the concrete 3 during the slip moulding process in order not to create any wrinkles on the basalt fibre rovings or in order to stabilise the tower 1.

(19) The basalt fibre rovings 2,8,9,10 can be embedded as a supplement to conventional iron bar reinforcement 6 or the conventional iron bar reinforcement 6 can be embedded as a supplement to the basalt fibre rovings 2.