WO2012050540A1

WO2012050540A1 - Wind turbine (embodiments)

Info

Publication number: WO2012050540A1
Application number: PCT/UA2011/000091
Authority: WO
Inventors: Владыслав Евгэновыч КУДРЯШЭВ; Вячэслав Мыколайовыч ТКАЧЭНКО
Original assignee: Kudriashev Vladyslav Yevguenovitch; Tkachenko Viacheslav Mykolayovitch
Priority date: 2010-10-11
Filing date: 2011-10-07
Publication date: 2012-04-19
Also published as: UA95586C2

Abstract

The invention relates to wind power engineering. The wind turbine with a vertical axis of rotation comprises a hollow rotor with blades attached to the shaft thereof, and a drive. The rotor is in the form of a truncated cone and is situated in the centre of a pyramidal frame. The blades are in the form of right-angled triangles having truncated acute angles and are convexly curved. The blades are further attached to a horizontal disc, which serves as the flywheel and bearing plate of the rotor. According to a first embodiment, the disc and the ring in which it is mounted are situated on a platform formed by the bottom supports of the frame. According to a second embodiment, the rotor is disposed on a rod in the centre of the pyramidal frame. In this case, the aforementioned disc is mounted on the rod, which is provided with a bearing. The invention makes it possible to produce a modular structure with easily replaceable components and increase the efficiency with which the wind flow is utilized.

Description

WIND POWER TURBINE (options)

The invention relates to a wind energy turbine with a vertical axis of rotation of the rotor and can be used in the field of renewable energy, specializing in the use of environmentally friendly kinetic wind energy to convert it into electrical energy as an autonomous energy source in places where it is absent: in tourist camps, campsites , small cafes and hotels, cottages, greenhouse farms, high-rises and the like.

All over the world there is the problem of creating highly efficient wind power plants that could use wind of a variable direction and a different speed range: from weak to strong and stormy.

Research and development in the field of wind energy are aimed at successfully solving some of these problems. Today there are no wind engines or wind turbines that would completely solve these existing problems. Despite their external divergence, turbines with vertical and horizontal axes of rotation are similar systems. A variety of designs are proposed, based on the ability to pick up mild to moderate winds, for example, in US Pat. N22406268 2406268 (IPC F03D3 / 06; F03D3 / 00, 1946), NS4035658 (IPC2 F03D9 / 00, 1977) and N ° 4850792 (IPC F03D7 / 06; F03D7 / 00; F03D7 / 06, 1989). In another device, U.S. Patent No. 4834610 (Bond, IPC4 F03D7 / 06, 1989) uses wind at a variable speed using modern speed controllers. Many devices are designed so that when the wind reaches a certain level, they add up and / or go into weather mode. Although using these techniques provides for the preservation of the structural integrity of the wind engine, the ability of the device to produce energy is reduced.

In other devices, such as in US patent N25391926 (IPC F03D3 / 04; F03D3 / 06; F03D3 / 00; F03D3 / 04, 1995), an attempt was made to use strong winds coming from any direction, but the winds are from weak to moderate they are not able to generate a torque sufficient for continuous reliable energy production, and the destructive characteristics of strong winds create conditions under which it becomes economically unprofitable to manufacture a wind turbine that can produce mechanical energy only in time periods of strong winds.

Wind power turbines are known in which the rotor drive shaft is located vertically, and the blades are long, usually arcuate, attached to the upper and lower parts of the tower and described in the works of V.V. Gadaychuk and V.P. Kosenko. Dynamo installations for energy installations. sherts them on Onip Mater1al1v i Teopifl equipment 2008. N ° 82 pp. 31-38, patent WO / 2008/047238. IPC F03D 3/00 (2006.01)] and patent RU N22322610, IPC F03D 3/00 (2006.01), 2008. Due to the vertical arrangement of the rotor drive shaft, such turbines "capture" the wind that blows in any direction and for this they it is necessary to change the position of the rotor when changing the direction of wind flows. The performance of such wind turbines is affected by dynamic loads caused by aerodynamic interaction wind flows and moving structural elements and centrifugal forces of simple rotation of the rotor. .

Many designs are made lightweight, not sufficiently fixed and from materials that do not meet the requirements of these materials. A number of such devices have a large number of moving parts, such as rotors, stators, weathercocks, screens, etc. These parts not only degrade the integrity of the device, but also require ongoing maintenance, repair, and / or replacement. For a device that can only produce a few kilowatts of energy, the costs begin to exceed the benefits.

The wind turbine is also known, patent RU 2279567 (IPC7 F03D3 / 06, Application: 2004106624/06, 09/26/2001), which uses large air columns to convert the energy of the air flow into mechanical energy through the use of a long vertical axis. This energy can be transferred further from the turbine to use its direct action on the water pump or to drive an electric generator, or a device that uses energy. The turbine contains a number of rotors and stators, which during operation interact with wind flows of interchangeable directions. A better embodiment of the invention has fixed stators designed to more efficiently direct flows to a rotor cell assembly having rotor blades.

The stator blades are made rectilinear and inclined to the optimum angle so that they produce a minimal effect on the loss of kinetic wind energy. An improvement of the wind turbine is the use of modern lightweight structural materials, such as lightweight composite multi-ball materials, the best of which are multi-ball honeycomb panels, which usually have a honeycomb core made of aramid fiber with a variety of non-metallic cladding balls, for example, epoxy, fiberglass, phenolic and Kevlar.

Alternatively, light metals such as aluminum can be used in the construction of the honeycomb core. Facing balls can be laminated. However, the performance of such wind turbines is also affected by such main factors as dynamic loads caused by the aerodynamic interaction of wind flows and moving structural elements, centrifugal forces of simple rotation of the rotor and Coriollis forces of inertia of the interaction of the rotational and rotational movements of its elements. In addition, the shape of the blades is such that the wind flow provides additional resistance to those blades that return to their original position to capture the wind flow. In this case, the rotational movement of the turbine is inhibited and a decrease in the use of the total wind flow through the “draft”, which is formed when the flow passes from above, is generated, the flows are quenched and a reverse flow is formed when the wind direction is changed.

The specified wind turbine operates on bearings and is designed for high revolutions, so it creates noise. In case of failure of the upper leveling vane and establishing the direction of the wind flow, the efficiency of the wind turbine has a power loss. When used on the ground, efficiency is lost design, limited use due to the fact that it is designed to work on high-rise buildings and has low-power generators.

Also known wind turbine with a vertical axis of rotation, patent UA Ns 61447, IPC7 F03D3 / 00, F03D3 / 06, 2003, bull. Nfl 11, consisting of a rotatably mounted cavity bar with rotary elements with working elements made in the form of blades having an involute shape in the plane of the rotor axis perpendicular to the rotor axis, the rotor has an unpaired number of working elements made in the form of blades, which are in the plane of the parallel axis rotations of the rotor are in the form of a Savonius rotor, turning into a conical screw rotor, which in the lower part passes into a cylindrical involute shape.

This design does not comply with safety standards due to the fixing of the axis on the cable extensions, therefore it does not have a reliable frame frame; there is no protection of the rotating elements of the wind turbine; the geometry of the blades is subjected to destructive inertial loads during the reverse movement of the streamlined part of the blade with respect to the oncoming flow of the working direction of the wind, thereby reducing the efficiency wind turbine. The execution of the rotor of the wind turbine is continuous, with combined elements in the form of a blade of complex shape, creates an uneven twisting of the vortex and additional resistance in each of the sections of the rotor blades, and therefore, low efficiency of converting the energy of the wind flow into mechanical energy. Cable extensions do not provide constant rigidity and static load-bearing structures. They need to be tightened periodically, and improper tension or hauling can lead to a curvature of the axis of rotation of the rotor and impede its course depending on the change in the direction of wind flows, which, in turn, leads to deformation and destruction of individual structural elements (bearings, rods, blades, axis). In addition, there is a difficulty in servicing and repairing a wind turbine, for example, when bearings fail, it becomes necessary to completely disassemble the rotor.

Also known is a wind power installation, which contains a wind turbine with a vertical axis of rotation, UA patent for utility model N ° 32145, IPC (2006), F03D1 / 00 F03D3 / 00, 2008, bull. N ° 9, consisting of a hollow rotor mounted on bearings with an unpaired number of working elements made in the form of blades having an involute twist 120 ° along the rotor in the plane of the axis of rotation with a vortex trap at the end, and the wind turbine rotor mounted on magnetic bearings, fixed in a stationary support, and connected to an energy conversion unit.

The exciting involute wind at the end of the blade creates additional loads on the blades, which in case of a strong and stormy wind can lead to the destruction and separation of the blade working plate itself. There is a predisposition to the destruction of the installation in strong winds. Due to the large dimensions of the structure and high windage, there is a problem of its installation on the roofs of buildings, and due to the technologically complicated manufacturing and balancing of the blades, as well as the high cost of the structure, it becomes economically unprofitable.

The closest in combination of features and technical result to the invention, which is claimed to be a wind turbine with a vertical axis rotation according to the patent UA N213993 A, IPC (2006), F03D1 / 00 F03D3 / 00, F03D3 / 06 (2007.01J, 1997, bull. N ^Q 2. The wind turbine contains a hollow conical rotor with working elements directed upward from the mounting surface and mounted on the rod, equipped with a drive connected to the rotor. The working elements of the rotor are attached to its axis and made in the form of blades having an involute shape in a plane perpendicular to the axis of rotation of the rotor.

The presence of a conical rotor with an angle at the apex and height, which depends on the required power, installing it on a rod and fixing it with braces to the mounting surface requires high lifting of the rotor above the mounting surface and its stationary placement on a certain section of this surface. A V-belt drive does not provide a complete transmission of torque to the generator; slippage when the generator starts is possible. Cable extensions do not provide constant stiffness and static. From time to time it is necessary to tighten the V-belt drive and cable stretch marks, and their incorrect tension or hauling can lead to a curvature of the axis of rotation of the rotor, blades and rods, which leads to deformation and destruction of individual structural elements (bearings, rods, blades, axles). This requires additional costs for both maintenance and repair of the wind turbine.

The basis of the invention is the task of creating a wind energy turbine (options) with a vertical axis of rotation of the rotor efficient, lightweight, universal, modular with easily replaceable structural elements, which can work without additional devices at wind speeds of different ranges and variable directions through improving the shape of the blades that could would significantly increase the utilization of the wind flow and structural design and placement of elements of the proposed design ui.

To solve the problem in a wind turbine with a vertical axis of rotation, containing a hollow conical rotor pointing upward, blades having a plane in the plane perpendicular to the axis of rotation of the rotor are involute and mounted on the rotor axis and the drive associated with the rotor, according to the invention, is hollow the conical rotor is made in the form of a truncated cone and is placed in the center of the four-support rigid skeleton having the shape of a pyramid, to the upper part of the support of which the axis of the rotor with the skeleton is attached with a cross, the pyramid is mounted on the lower skeleton supports of the skeleton, and the blades are made in the form a rectangular triangle truncated in a reamer at sharp corners, which is curved along the involute and horizontally is additionally mounted on a disk that acts as a rotor flywheel and its carrier plate, which placed in a ring mounted on the disk, the ring with the disk is placed on the table of the lower supports of the frame, under which there is a toothed belt drive that connects the axis of the rotor to the generator, which is located on the installation site of the generator. The blade consists of vertical and horizontal four-layer panels and a corner. Its inner surface is made rough. The blade panels are made of polymeric materials. Along the perimeter between the lower supports of the frame below the level of the generator, solar panels are additionally installed, which are oriented to the position of the sun during the bright part of the day. An additional beacon is installed on the crosspiece, which determines the position of the turbine relative to other objects during the dark part of the day and a lightning rod.

In another embodiment, to solve the problem in a wind energy turbine with a vertical axis of rotation, containing a hollow conical rotor pointing upward, blades having in a plane perpendicular to the axis of rotation of the rotor, an involute shape and mounted on the axis of the rotor and the drive associated with the rotor, according to of the invention, the hollow conical rotor is made in the form of a truncated cone and placed on a rod in the center of a rigid pyramid-shaped frame, to the upper part of the support of which, by means of a cross, is connected inena the rotor axis with the frame, the frame supports in the lower part are interconnected by beams, the blades are made in the form of a rectangular triangle truncated in the reamer at sharp angles, which is curved along the involute and additionally horizontally mounted on the disk, which serves as the rotor flywheel and its carrier plate mounted on a rod with a fifth, and between the beam and the disk on the racks of the platform there is a panel under which a gear-belt drive is located on the generator platform, which is mounted on the rod bracket. The blade consists of vertical and horizontal four-layer panels and a corner. The inner surface of the blade is made rough. The blade panels are made of polymeric materials. An additional beacon is installed on the crosspiece, which determines the position of the turbine relative to other objects during the dark part of the day. A lightning rod is additionally installed on the crosspiece.

The execution of a hollow conical rotor in the form of a truncated cone and its placement in the center of a four-support rigid frame in the form of a pyramid, its installation on the lower supports of the frame and connection with the frame of the rotor axis with the disk, which acts as a rotor flywheel and its carrier plate for mounting the blades, allows stability and smooth running of the working part of the rotor of a wind energy turbine, increases its performance by providing a rigid metal structure, which increases reliability, stability flaxality and trouble-free operation, eliminates vibration during rotation of the rotor, increases efficiency

The execution of the four rotor blades in the form of a right-angled triangle truncated in a reamer at sharp angles, which is curved along the involute and horizontally additionally mounted on the disk, which serves as the rotor flywheel and its carrier plate, allows for an efficient intake of the wind flow. Each of the blades of the conical rotor has the shape of a truncated cone, curved along the involute according to the following formula:

πά

a = -

t where

d is the diameter of the circle,

m is the number of parts into which the circle is divided.

The geometry of the blade involute is created in the form of a truncated cone of cylindrical shape, which, in turn, allows the turbine to overcome oncoming air currents without clapping and noise, creating a tornado swirl along the rotor axis, discharging and relieving mechanical stress on the turbine axis, which is important for a wind turbine of this type (affects the longevity of work). This effect is not observed in world analogues of devices of this type.

During rotation, the rotor creates a spiral-vortex flow, which creates a vacuum in a spiral around the axis, which weakens the load on the main working part of the wind turbine, and the closed base of the wind energy turbine, which collects the wind, increases the lever, the rotor torque and, accordingly, its efficiency. d.

The blades are made of durable and flexible polymeric materials, which, when the rotor rotates, gives the design a sliding airflow around it. The inner surface of the blade is specially made rough for a stronger capture of the oncoming wind flow, which increases the efficiency wind power turbines.

The axis of the wind energy turbine is mounted on a tetrahedral tubular frame assembled in the form of a pyramid, which gives the structure special strength and reliability.

The design of the wind energy turbine additionally provides the possibility of installing solar panels oriented to the position of the sun during the bright part of the day, a pulsed beacon that determines the position of the turbine relative to other objects during the dark part of the day, a lightning rod to protect high-rise buildings from lightning damage, as well as the installation of other lighting and advertising devices.

The invention is illustrated by drawings, where in FIG. 1 - shows a General view of the four-support frame structure of a wind energy turbine; in FIG. 1a, FIG. 16 and FIG. 1 c - the position of the phased assembly of the four-support frame structure of a wind energy turbine; in FIG. 2 is a general view of a four-support frame structure of a wind energy turbine; in FIG. 2a is the same, a top view, where A, B, C, D touches the upper supports of the frame; in FIG. 3 is a diagram of a rotor of a wind energy turbine interacting with an air stream, where V is the direction of rotation of the rotor, W is the zone of capture of the wind stream, F is the zone of flow around the wind stream; in FIG. 4 is a general view of a four-support wind turbine; in FIG. 5 is a general view of a variant of a four-support wind turbine; in FIG. 5a is the same, a top view.

The wind energy turbine, figures 1 - 2a, consists of a hollow conical rotor made in the form of a truncated cone and placed in the center of a four-support rigid frame, which has the shape of a pyramid, to the upper part of the support (2) which is connected via the crosspiece (1) to the axis (6) ) rotor. The pyramid is mounted on the lower, made in the form of a triangle, supports (9) of the frame. The blades (3) are made in the form of a rectangular triangle truncated in a reamer at sharp angles, which is curved along the involute and horizontally additionally mounted on the disk (4), which acts as a rotor flywheel and its carrier plate, which is placed in the ring (5) installed on disk (4). The ring (5) with the disk (4) is placed on the table (7) of the lower supports (9) of the frame, under which there is a toothed belt drive (1 1), which connects the axis (6) of the rotor with the generator (8), which is located on installation site (10) of the generator (8).

The blade (3) consists of vertical and horizontal four-layer panels and a corner, and the inner surface of the blade (3) is made rough. The blade panels (3) are made of polymeric materials. Along the perimeter between the lower supports (9) of the frame below the turbine level, solar panels are additionally installed, which are oriented to the position of the sun during the bright part of the day. An additional beacon is installed on the crosspiece (1), which determines the position of the turbine relative to other objects during the dark part of the day and a lightning rod. (Not shown in the drawing). In another embodiment, a wind energy turbine with a vertical axis of rotation, Figures 5 - 5a, consists of a hollow conical rotor made in the form of a truncated cone and placed on the rod (7) in the center of the rigid frame, which has the shape of a pyramid, to the upper part of the support (3) which with the help of a cross (1) attached to the axis (2) of the rotor. The supports (3) of the frame in the lower part are interconnected by beams (10). The blades (4) are made in the form of a rectangular triangle truncated in a reamer at sharp corners, which is curved along the involute and horizontally additionally mounted on the disk (1 1). The disk (1) is mounted on the rod (7) with the fifth (8). Between the beam (10) and the disk (11) on the racks of the platform (5) there is an upper panel (12), under which a gear-belt drive (not shown) is installed on the generator platform (9), which connects the rotor axis (2) with a generator (9), which is fixed to the rod (7) with an arm (6).

The blade (4) consists of vertical and horizontal four-layer panels and a corner. The inner surface of the blade (4) is made rough. The blade panels (4) are made of polymeric materials, such as Parabeam fiberglass, fiberglass, chopped glass material, SPHERETEX glass material, unsaturated polyester resins in accordance with GOST 27952. An additional beacon is installed on the crosspiece (1), which determines the position of the turbine regarding other objects during the dark part of the day and a lightning rod. (Not shown in the drawing).

The design of the wind energy turbine and its variant additionally provide for the possibility of installing solar panels oriented to the position of the sun during the bright part of the day, a pulsed beacon that determines the position of the turbine relative to other objects during the dark part of the day, a lightning rod to protect high-rise buildings from lightning damage, and installation of other lighting and advertising devices.

The operation scheme of the rotor of a wind energy turbine interacting with the air flow is the same in both versions of the device and is clearly illustrated in FIG. 3, where V is the direction of rotation of the rotor, W is the capture zone of the wind flow, F is the zone of flow around the wind flow. In wind power a turbine with a vertical axis of rotation, a hollow conical rotor in the form of a truncated cone rotates and captures the wind in any direction. During rotation, the rotor forms a spiral-vortex flow, which goes up and creates a rarefaction in a spiral around the axis (6) (in the embodiment, the axis (2)). This is achieved due to the geometric shape of the rotor and its blades (3) (in the variant - blades (4)), which reduces the load on the main working part of the wind power turbine, and the closed base of the wind power turbine, which acts as a flywheel of the rotor and its bearing plate (blades ( 3), a disk (4) and a ring (5); in the embodiment, blades (4) and a disk (12)), which collects wind, increases the shoulder, the rotor torque and, accordingly, increases its efficiency From the rotor, which rotates, the rotation is transmitted through a gear-belt drive (1 1), which connects the axis (6) of the rotor to the generator (8), which is located on the mounting platform (10) of the generator (8). In the embodiment, from the rotor that rotates, the rotation is transmitted to the generator (10) through a toothed belt drive (not shown) installed on the platform (9), which connects the axis of the rotor (2) with the generator (10).

The wind turbine operates in the range of operating wind speeds from 2 m / s to 50 m / s (when the rotor stops), operating temperature - from minus 25 ° С to plus 60 ° С, relative humidity of 98% at a temperature of 25 ° С, at rain intensity 5 mm / min., with snowfall, with fog, with dew, with frost, with icing, its efficiency accounts for 94 - 95.5%.

The advantages and uniqueness of a wind turbine are that:

• four-support pyramidal design gives reliability and strength to this mechanism;

• easy assembly, installation, which does not require special skills and complex lifting mechanisms (simplicity of design and reliability);

• the ability to install on various planes: on roofs, technical buildings, on the ground, on masts, walls, etc .;

• complete noiseless operation of the rotor (in comparison with horizontal-axis and vertical-axis turbines of this type);

• additionally, in case of stormy and hurricane winds, cable extensions are used to insure against mechanical damage wind turbine in extreme weather conditions (protection against damage);

• a wind power turbine complies with all existing standards and requirements for both electrical and mechanical safety of rotating components and mechanisms;

• the geometry of the blade involute is created in the form of a truncated cone of cylindrical shape, which allows the turbine to overcome the oncoming air currents without clapping and noise, creating tornado twist along the rotor axis to dilute and relieve mechanical stress on the turbine axis, which is important for a wind power turbine of this type (affects on durability);

• under certain requirements for the installation and installation of a wind turbine, it is possible to produce a pyramid of either a tetrahedral or a trihedral type, which does not contradict this device with respect to safety and reliability standards;

• in desert and marine conditions, protection is provided against the ingress of sand and water into the main mechanical and electrical parts of a wind energy turbine (protection in the form of a casing).

Claims

CLAIM

1. Wind turbine with a vertical axis of rotation, containing a hollow conical rotor pointing upward, blades having in a plane perpendicular to the axis of rotation of the rotor, an involute shape and mounted on the axis of the rotor, a drive associated with the rotor, characterized in that the hollow conical rotor made in the form of a truncated cone and placed in the center of a four-support rigid frame, which has the shape of a pyramid, to the upper part of the support (2) which is attached to the axis (6) of the rotor with the frame, peir using a cross (1) the ida is mounted on the lower supports made in the form of a triangle (9) of the frame, and the blades (3) are made in the form of a rectangular triangle truncated in the scan at sharp angles, which is curved along the involute and horizontally additionally mounted on the disk (4), which performs the role of the rotor flywheel and its bearing plate, which is located in the ring (5) mounted on the disk (4), the ring (5) with the disk (4) are placed on the table (7) of the lower supports (9) of the frame, under which the gear a belt drive (1 1), which connects the axis (6) of the rotor with the generator (8), which ory located on the placement surface (10) of the generator (8).

2. Wind turbine according to claim 1, characterized in that the blade (3) consists of vertical and horizontal four-layer panels and a corner.

3 Wind turbine according to claim 1 or claim 2, characterized in that. the inner surface of the blade (3) is made rough.

4. Wind turbine according to any one of claims 1 to 3, characterized in that the blade panel (3) is made of polymeric materials.

5. A wind energy turbine according to any one of claims 1 to 4, characterized in that around the perimeter between the lower supports (9) of the frame below the generator level, solar panels are additionally installed that are oriented to the position of the sun during the bright part of the day.

6. Wind power turbine according to any one of claims 1 to 5, characterized in that an additional beacon is installed on the crosspiece (1), which determines the position of the turbine relative to other objects during the dark part of the day.

7. Wind turbine according to any one of claims 1 to 6, characterized in that a lightning rod is additionally installed on the crosspiece (1).

8. Wind turbine with a vertical axis of rotation, containing a hollow conical rotor pointing upward and placed on the rod, blades having in a plane perpendicular to the axis of rotation of the rotor, an involute shape and mounted on the axis of the rotor, a drive associated with the rotor, characterized in that, the hollow conical rotor is made in the form of a truncated cone and placed on the rod (7) in the center of the rigid frame, which has the shape of a pyramid, to the upper part of the support (3) of which the axis (2) of the mouth is connected with a cross (1) the frame with the frame, the frame supports (3) in the lower part are interconnected by beams (10), the blades (4) are made in the form of a rectangular triangle truncated in the scan at sharp angles, which is curved along the involute and additionally horizontally mounted on the disk (12) which acts as a rotor flywheel and its carrier plate mounted on a rod (7) with a fifth (8), and between the beam (11) and the disk (12) on the platform racks (5) there is an upper panel (13), under which the platform (9) of the generator (10) is a toothed belt drive that connects the axis (2) of the mouth ra with the generator (10) which is fixed on the rod (7) the bracket (6).

9. Wind turbine according to claim 8, characterized in that the blade (4) consists of vertical and horizontal four-layer panels and a corner.

10. Wind turbine according to claim 8 or claim 9, characterized in that. the inner surface of the blade (4) is made rough.

11. Wind turbine according to any one of paragraphs.8-10, characterized in that the blade panel (4) is made of polymeric materials.

12. Wind turbine according to any one of paragraphs.8-11, characterized in that an additional beacon is installed on the crosspiece (1), which determines the position of the turbine relative to other objects during the dark part of the day.

13. Wind power turbine according to any one of paragraphs.8-12, characterized in that a lightning rod is additionally installed on the crosspiece (1).