ITMI20101677A1 - WIND GENERATOR OF ELECTRICITY. - Google Patents

Description

WIND GENERATOR OF ELECTRICITY

DESCRIPTION

The present invention relates to a wind generator of electrical energy based on a system of ropes and sails, as described in its general lines, for example in the document US-2003/0001393-A1.

The need to find renewable electricity sources has long been felt in order to reduce dependence on petroleum derivatives and to increase non-polluting energy sources. Among these, wind energy has taken on considerable weight, both for the relatively modest environmental impact, and for the fact that there are numerous sites that can be exploited for this purpose. The research is therefore aimed at identifying new systems, more powerful and cheaper than those known so far, using ropes and surfaces suitably prepared to increase the performance of energy capture and transformation.

The wind power generation plants currently in use that have had particular success over time are made up of single propellers, rotatably mounted on horizontal axis shafts, coupled to single generators, shafts and propellers being mounted inside nacelles, supported by single poles so that rotatable around a vertical axis. This type of system is, on the one hand, designed to be able to orient itself, by rotating around a vertical axis, so that the rotating surface of the propeller is normally arranged for the flow of air and, on the other hand , equipped with variable pitch propellers, which can thus vary their pitch according to wind speed. In order for the plant to have an interesting yield - taking into account that the usable wind energy is only that deriving from the front, hit by the wind, of the helix envelope circle, and that the linear speed of the The surface of the propeller blade in the center of the circle is significantly smaller than that at the tip of the blade - propellers with blades of adequate size and number must be used. Generally, for example, a propeller having a diameter of 100 meters produces about 2 MW; It is also known that these yields are relatively modest, in the face of very high installation costs.

In addition to this obvious disadvantage, these systems bring other annoying drawbacks: they are in fact very noisy, create problems with the trajectories of birds, sometimes cause the projection of ice that has previously formed on the propellers, and finally also have a very environmental impact. criticized.

Furthermore, in order for the propellers to have sufficient wind resistance, especially when they are mounted on very high pylons, massive foundation structures are required for their support and particularly consistent soils on which to use them.

In order to solve the aforementioned problems of traditionally known structures, numerous findings have been made suitable for obtaining wind energy with expedients aimed at reducing the cost / efficiency ratio. In particular, plants have been created to exploit continuous or alternating movements of wind surfaces which - essentially like sails - are held in stable engagement on horizontal or vertical ropes, and are dragged by the thrust of the wind.

Among these, wind generator systems are distinguished in which the wind capture surfaces have the shape of a hemispherical parachute, which understandably drag the ropes in the direction in favor of the wind and which close on the return against the wind, the open surfaces being load-bearing to rise, and closed in fall, with alternating motions.

Complex structures have also been proposed, consisting of a plurality of kites arranged in scale on two pairs of cables, these being controlled by winches fixed to horizontal radial beams, which drag a large vertical axis drive wheel, mounted on a tower; these structures are suitable for investing large quantities of flow, up to the height of air traffic.

However, even these realizations are very complicated, given the evident complexity of managing the positioning of the kites far from the bases, especially during the launch phase and due to the variability of atmospheric stresses at different altitudes. We therefore opted to find solutions that would make the wind generator system simpler and cheaper.

Since the systems built and described up to now presuppose use in any position or wind condition, we went to evaluate whether - in order to create less complex systems - it was possible to isolate situations in which it was not necessary to foresee the multi-directionality of the wind, and consequently adapt the systems to such situations. Studies on the subject have shown that the most convenient energy use would involve the use of a rope moved, by wind surfaces, transversely to the movement of unidirectional air masses, even if in the opposite direction such as breezes: yes it could thus avoid creating driving surfaces that can be oriented in any direction, as it is sufficient that the wind capture surface can oscillate, both in response to variations in incidence due to the different speed of the flow, and as a function of enslavement to the optimal speeds of the generators .

Such an optimal condition is actually achievable in nature in particular situations, but in any case which may have a certain diffusion, for example in alpine or mountain valleys. Typically, in fact, favorable positions for the construction of wind farms with good efficiency are located where the orography, topography and meteorological conditions create alternating day and night pressure jumps, as in the case of breezes, or between seas, plains, mountains. or continents with seasonal alternations as for the trade winds.

The purpose of the present invention is therefore to propose a low-cost wind energy generator system, which is particularly effective in areas where the wind flow is almost unidirectional, making use of ropes moved by wind surfaces transversely to the movement of masses of air, even if in the opposite direction as in the case of breezes.

A plant of this type is illustrated in US-2003/0001393-A1 and comprises two endless chains, which are each made to circulate on a pair of toothed idle pulleys and which carry surfaces subject to the action of the wind. These aeolian surfaces are made as flexible sails - of the type of sails for boats, in cotton or synthetic fibers - or as rigid sails, with a rectangular or rhomboidal shape; in both cases they are supported by two horizontal rods, or booms, one on the upper edge and the other on the lower edge. The ends of these two booms, on the luff side of the sail, are respectively anchored to the two chains, in a first position, while the opposite ends are hooked to spacer arms, in turn anchored to the two chains in a second position, set back from to the first.

The deflection pulleys are mounted so that the wind surfaces hooked to a forward path of the chain, for example the one that moves on the front side, windward, are at a different level from those that are hooked to the return path of the chain , ie those that move on the rear or leeward side. In this way, both the upwind and leeward sails take full advantage of the energy of the wind flow, without creating any real interference.

A first drawback of the system described in this patent is that it does not provide any indication of how the sails can assume - passing from the windward position to the leeward position - the configuration suitable for exploiting the action of the wind in a congruent way. In other words, if we take into account that, in the circulation of the endless chains, one side of them moves in a direction that is necessarily opposite to the direction of its other side, while the action of the wind is always in one direction. direction roughly perpendicular to said two sides, it is evident the need for the sails on the windward side to assume a configuration such as to translate the thrust of the wind into a thrust on the chain in the opposite direction to the thrust exerted by the sails from the leeward side. In the aforementioned document US-2003/0001393-A1, although the need to move the sails so as to orient them on the windward side differently than on the leeward side is indicated, no teaching is provided for this purpose.

A second, more serious, drawback is given by the fact that the sails described here have a substantially rigid structure, in the sense that there is no solution to the problem of adapting the system to very different wind conditions, not so much in in terms of wind direction, as in terms of flow energy. It is well known that in the flow of the wind that runs through a valley - and which therefore has a substantially stable direction - instead, significant variations in wind speed are produced, for example from 5 to 15 m / sec. Wanting to transfer the teachings of sailing to this field, it is necessary to think about carrying out a reduction of the sails when the flow of the wind exceeds certain values, in order not to risk the tearing of the sails.

A solution to the first of these drawbacks is offered in document US-2008/0007069 due to the fact that the sails are guided along a guide - which is clearly illustrated for example in figure 11 of this document - which leaves a space free, between the front forward path and the rear return path, sufficient to allow the free change of tack of the sails, simply under the action of the wind. However, this patent - due to the fact that it mainly concerns a plant intended to exploit not the flow of the wind, but the flow of water for example in a stream - requires that the windward side is at the same level as the side downwind; but this situation is not comparable with that of the wind on the sails, where it is absolutely essential that the section downstream of the system, or the leeward side, is not subject to the turbulence problems that the upstream section can generate if find at the same level. For this reason it is believed that the prior art closest to the present invention is that illustrated in the above-mentioned US-2003/0001393-A1 patent which, mainly concerned with this problem, finds a solution by arranging the return wheels on axes slightly oblique with respect to the vertical, so as to obtain that the leeward section is at a different altitude from that of the upwind section.

It is therefore an object of the present invention to propose a wind power plant for the generation of electrical energy, of the general type according to US-2003/0001393-A1, which nevertheless overcomes the limitations and drawbacks that result from this. Said object is achieved by means of a wind power generator having the characteristics indicated in claim 1), the secondary claims defining some preferred characteristics.

The invention is now described with reference to the attached figures, in which:

- fig. 1 is a perspective, panoramic view of a possible embodiment of a wind generator system according to the invention, mounted transversely to an Alpine valley;

- fig. 2 is a side view of one of the end supports of a first embodiment of the implant according to the invention, of which

- fig. 2a is a front view, showing in particular the arrangement of the wind surfaces with respect to the pair of return wheels of the support cables;

- fig. 3 is a view similar to that of fig. 2 of a second embodiment of the system according to the invention;

- fig. 4 is a view similar to fig. 2a relating to the embodiment of fig. 3;

- figs. 5 and 5a schematically show the coupling point, forming a joint, of a wind surface to the relative carrying cable, in two different working conditions;

- fig. 6 is a sectional view of the coupling and handling system of the wind surface, schematized in figs. 5 and 5a;

- figs. 7a to 7c are schematizations in plan of the movement and control system of the wind farm surfaces of the plant according to the invention;

- fig. 8 is a view, also in plan, of a detail of the wind surfaces of figs. 7a to 7c;

- fig. 9 and 9a are a front view and plan view respectively of a wind surface according to the invention, in which stiffening elements are highlighted; And

- fig. 9b is a partial view, similar to that of fig. 9, which shows a luff mast made as a â € œroll-stapleâ €.

As schematized in the illustration of fig. 1, a possible scheme of a wind power generating plant according to the present invention comprises two supporting pillars P and P ', roughly arranged on the ridges on the two sides of the valley, and at least one pair of ropes 1, 1a, substantially parallel to each other, having each course has a double catenary, which run from one pylon to the other, transversely to the valley.

Each of these ropes is mounted sliding around a respective pair of return wheels 2, 2a; two wheels 2, 2a are provided at one end of the catenary, on the pole P, and two other wheels are provided at the other end of the catenary, on the pole Pâ € ™, in order to keep the catenary in correct tension.

Several wind surfaces 4A, 4B are anchored to the two ropes 1, 1a. . . and up to 4N-3, 4N-2, 4N-1, 4N. Since these aeolian surfaces are similar to sails (here and in the following the term `` sail '' is used, considered as equivalent to the term `` wind surface '', but it is understood that this term must be considered applicable to any other surface that is not a sail in the strict sense, but which performs an equivalent function), for the purpose of a better understanding of the invention below we will use terms borrowed from the nautical sector, well known to experts in the sailing sector, and which are carried well in the description of the preferred embodiment of the present invention.

The fixing of each of these sails to the ropes 1, 1a takes place by anchoring the respective luff 5 to one (1) and to the other rope (1a) by means of pairs of hooking elements 6 and 6a (fig. 2 and 2a); the hooking elements 6, 6a of each pair are each fixed to a respective rope (1, 1a) in positions which correspond to each other on a vertical alignment, so that the luff of each sail is arranged substantially vertically.

The pairs of hooking elements 6, 6a are also fixed to the respective ropes (1, 1a) at equal mutual distances along the length of the ropes (1, 1a), so that each sail can extend in the space included in this distance.

Since all the coupling elements 6 are fixed on the cable 1 and respectively all the coupling elements 6a are fixed on the cable 1a, each wind surface 4 extends with its luff 5 between the cable 1 and the cable 1a.

The wind surfaces are all positioned with the same configuration and with the same orientation with respect to the direction of the support catenaries; with respect to the action of the wind, however, they appear with the tack in the opposite direction on the windward side and on the leeward side of the catenaries, so that they tend to push the catenaries always in the same direction. In other words, they are able to drag the respective carrying ropes 1, 1a so as to make them slide in parallel, to circulate on respective return wheels 2, 2a.

A current generator G is coupled to each of the wheels 2, 2a (not shown in detail, as it is completely known per se, and in any case not forming part of the present invention) which, as well as is well known, is capable of to supply an electric current substantially proportional to the rotation speed impressed by the movement of the ropes.

These wheels 2, 2a are positioned at a reciprocal distance on support arms 3 (visible in fig. 2), rotatably mounted around inclined pins 3a; preferably these arms 3 are oriented substantially parallel to the sliding direction of the catenary in its position closest to the wheels 2, 2a, while the pins 3a are substantially perpendicular to said arms 3.

The pins 3a are in turn each carried by a respective bracket 3b, which is anchored in a guide 3c forming part of a rigid support, such as one of the pillars P, P 'or the like.

It is important to note that, according to a first fundamental characteristic of the invention, the wheels 2 and 2a are fixed on the arms 3 with their two opposite surfaces, so that the surfaces of these wheels instead face one towards the other are completely free from supports; this arrangement is clearly visible in fig. 2 due to the fact that the arm 3 is hidden behind the wheel 2a while it is placed in front of the wheel 2 but, even more clearly, in the front view of fig. 2a, where you can see the luffs 5 of some sails that run between the two wheels 2 and 2a when passing over the wheels.

As shown in figs. 2 and 2a, and in more detail in fig. 9, the wind power surfaces 4 are constituted by sails with a substantially quadrilateral plan. As already said, the leading edge 5, or luff, of each sail is held taut between pairs of hooking elements 6, 6a provided respectively on one 1 and on the other rope 1a; the trailing edge 7, or leech, is instead held taut by sheets 8, which branch off from said trailing edge and hook onto the hooking elements 6, 6a of the sail that follows along the catenary (see again Fig. 9 ). Preferably, to fix the sheet 8 inside the sail, i.e. at a certain distance from the leech, giving it more quarter - in order to allow the free flow of the W flow (see fig. 9a), thus less deviated â € “the leech may be locally stiffened by ribs or by semi-rigid inserts 12, wider, as also illustrated in fig. 9.

In fig. 2a it can be seen clearly how the return wheels 2, 2a are not arranged in a single vertical plane; they are in fact arranged with their sub-vertical rotation planes - this term means that these rotation planes are oblique, of a relatively small angle, with respect to the common vertical axis of the brackets 3b - and also parallel and at least briefly spaced apart. In this way the wind surfaces, which are coupled between the two catenaries 1, 1a, can slide freely on the wheels 2, 2a, without interference between them when said ropes reverse their direction of travel passing precisely on the two wheels (this passage It is also clearly visible in fig. 1).

In the alternative embodiment illustrated in FIGS. 3 and 4 the problem of the interference of wind power surfaces is solved by providing a set of four wheels instead of two. More precisely, for the catenary 1 two wheels 2 and 2â € ™ are provided here, instead of one; the catenary 1 moves according to the arrow F and enters on the top of the wheel 2â € ™, then it descends and enters the wheel 2, from which it exits according to the arrow Fâ € ™. For the catenary 1a two wheels 2a and 2â € ™ a are provided here (see fig.

4) instead of one; the catenary 1a moves according to the arrow G and enters on the top of the wheel 2â € ™ a, then it descends and enters the wheel 2a, from which it exits according to the arrow Gâ € ™.

In this way it appears evident - in particular from the examination of fig.

4 - that no interference is generated in the space between the two catenaries. As illustrated in figs. 2a and 4, between the plane of rotation of the wheel 2 (or respectively of the pair of wheels 2, 2â € ™) and the plane of rotation of the wheel 2a (or respectively of the pair of wheels 2a, 2â € ™ a) is formed always a space that - thanks also to the fact that these wheels are cantilevered - is intended to give space to the free rotation of the wind power surfaces 4. In other words, thanks to this arrangement of the deflection wheels, the wind turbines 4 can climb over these wheels, in the transmission, passing through the space formed inside the shelves that contain the wheels.

According to another fundamental characteristic of the present invention, which is evident from figs. 2a and 4, and even better from figs. 5 and 5a, the movement of the sails inside the space between the idler wheels occurs with the luff of each sail which remains vertical, ie almost parallel to, and practically adherent, to the facing surfaces of the idler wheels. In other words, the upper and lower ends of the luff of each sail are anchored to the ropes 1 and 1a by means of hooking elements 6, 6a which (as better described below) comprise a joint 11, whose axis of rotation It is horizontal, ie approximately perpendicular to the return wheel 2, 2a with which they cooperate, which allows the luff to remain precisely vertical, ie approximately parallel, and practically adherent to the wheel. The purpose of this method of assembly is more evident in the following.

For a better understanding of this point, in the embodiment of figs. 5 and 5a reference is made to a luff in the form of a rigid shaft 5, the upper end of which is anchored to the cable 1 by means of one of the said coupling elements 6; thanks to the joint 11 mentioned above (and which is represented in greater detail in fig. 6), the shaft 5 is able to remain always arranged vertically (at least with respect to the representation of figs. 5 and 5a ), while the rope 1 passes from an oblique orientation in a descending direction towards the left of the drawing (fig.

5a) â € “when passing wheel 2'a, arrow G in fig. 3 â € “to an oblique orientation in the opposite direction (fig. 5), when moving away from wheel 2a, arrow Gâ € ™ in fig. 3.

It is evident that, for this purpose, the upper end of the shaft 5 must be free to rotate widely with respect to the coupling element 6, as is immediately evident from the comparison between the positions of fig. 5 and fig. 5a.

In the above, 5 indicates both the leading edge or luff of one of the sails 4 only, and a rigid hollow mast, to which the luff is attached; however it is understood that, with the same reference 5, any other element that performs the same function is indicated, that is any flexible luff - for example formed by textile or metal cable or by a textile or synthetic tube, or in carbon, possibly blown under pressure - or even a rigid fall element, such as a bar or a mast, to which the luff of the sail can be attached.

It is also possible to provide lighter structures, for which the presence of masts is not necessary, consisting of coupled airfoils, whose shape is determined by the pressure of gases lighter than the air.

Fig. 6 shows, on a significantly enlarged scale, the section of a possible embodiment of the coupling element 6, which comprises, on one side, a sleeve consisting of two rigid parts 9, 10, bolted to each other so as to clamp onto the rope 1 or 1a and, on the other hand, an appendage 10a of the part 10, equipped with a hole 10b for hooking the sail; this hole 10b is provided, in a simplified variant, for the insertion of eyebolts (not shown) for a simple attachment of the feeders 5 and sheets 8 and, in a preferred variant of the present invention, for the insertion of a pin 13, constituting the fundamental element of the joint 11. In this variant, one end of the pin 13 is intended to support the rotation of an luff shaft 5 and the opposite end is intended - possibly - to support of a reel 17 (fig. 6) for winding the sheets 8, as better specified below.

As is clear from fig. 6, a tubular seat is formed at one of the ends of the pin 13 (right end, with respect to the drawing), in which the upper end 5â € ™, shaped like a shank, of the luff shaft 5 can rotate.

In fact, to significantly improve the performance of the sails management system, it is envisaged to exploit the rotation of the mast 5 to reduce the sail by at least partially wrapping it. For this purpose, it is possible to use - in a manner known per se for example in the â € œjib rollerâ € devices of sailing boats - a control of the winding degree by means of a remote controlled motor drive, possibly in contrast to a spiral spring 21.

In a preferred embodiment of the present invention, however, provision is made for the luff 5 to rotate on itself without any motor, but with a particular winding device - shown in fig. 6 - which exploits the relative rotation movement of the shaft 5, together with the pin 13, with respect to the cables 1, 1a, during the path of these cables on the transmission wheels 2, 2a, as better described with reference to figs. 5 and 5a.

This rotation can take place to a determinable extent according to the desired degree of furling of the sails, that is, according to the different extensions of the sail required, for conditions of the wind flow speed from normal (sail fully deployed) and up to the extreme ones as in the stormy weather (considerably reduced sail).

This winding device - illustrated in fig. 6 â € “it has a very simple structure which, as already said, is able to substantially exploit the relative rotation motion of the shaft 5 and pin 13 assembly, with respect to the coupling elements 6, 6a integral with the rope 1, 1a, at the moment of passing from the position of fig. 5a to that of fig. 5, or vice versa, during the semi-rotation on the two return wheels 2, 2a at the ends of each catenary.

In particular, said winding device provides a bevel gear 14, which is mounted on the pin 13 which is normally free to rotate; this gear 14 is held stably in engagement with a corresponding bevel gear 15, integral in rotation to the shank 5 'of said shaft 5.

A stop device 16 (not better represented) allows the gear 14 to be locked, optionally, on the appendix 10a of part 10 of the coupling element 6 or 6a; in this way, the relative rotation of shaft 5 and pin 13 with respect to the gear 14, held fixed on the appendix 10a of the element 6, in the passage of the cable 1, or 1a on the return wheel (passage from the fig. 5a to that of fig. 5), causes a corresponding rotation of the gear 15, which in turn rotates the shaft 5.

According to a fundamental aspect of the present invention, this rotation of the shaft 5 on itself is capable of producing the winding and unwinding of the sail, and consequently its reduction or unfolding.

As is easily understood, looking at fig. 9, an indispensable condition for correct operation is that, in parallel with a reduction of the sail, by winding it around its own mast 5, an elongation of its sheets 8 is produced, hooked, as mentioned, to a mast 5 of the following sail.

This can be obtained by simple elastic elongation of the sheets or, according to a preferred embodiment, by hooking the ends of the sheets 8, opposite to the anchoring ones on the inserts 12, on a winding reel 17; as shown in fig. 9b, this reel 17 rotates integrally with the shaft 5 of the sail that follows, in the direction of movement of the ropes 1, 1a. It is obvious that the anchoring on the reel 17 must be carried out in such a way as to take into account that all the shafts 5 wind in the same direction, and with them also the respective reels 17, so that each sheet 8 must unwind from the reel when the sail is rolled up on the mast 5.

A more elaborate embodiment is that shown in fig. 6, which is designed to allow a more sophisticated control of the traction of the sheets 8. In this case, a reel 17a is fitted coaxially and freely rotatable with respect to the pin 13. The reel 17 is freely rotatable on the end of the pin. 13 opposite the gear 14, but it can also be blocked on the pin 13 by means of a special stop device 18 (also only schematized in fig. 6).

In operation, when the stop 16 blocks the gear 14 on the appendix 10a â € “so that the rotation of the pin 13 corresponds to a rotation of the gear 15 and therefore the winding of the sail, or its reduction â The stop 18 also locks the spool 17a on the pin 13; this also results in the rotation of the reel 17a which causes the sheet 8 to loosen.

As can be understood, thanks to this particular structure, the reduction of the sail occurs more effectively than the rotation of the mast 5 alone.

The action of the stop devices 16 and 18 can be maintained for the time necessary to obtain a preselected degree of sail reduction, in relation to the momentary wind conditions. Thanks to the fact that the stop devices 16 and 18 are independent, and therefore can be operated at different times, it is possible to have a much more precise control of the degree of reduction of the sail and its tension. This means that their holding action can be exercised for a shorter or longer period of the furling or unwinding movement of the sail, so that the effective part of the sail can be adjusted to the desired extent.

In order to maintain the selected degree of winding of the sail 4, independently of the momentary stops 16 and 18 and more stable, on the one hand, a snap coupling 19 is provided which locks the position of the mast 5 and, on the one hand, On the other side, a snap coupling 20, which blocks the reel 17a of the sheet 8.

Both the stop devices 16 and 18, and these snap couplings 19 and 20 (not better represented, as they are easily constructed by a person skilled in the art) are of the type that can be operated remotely - electrically. or via radio - and they can be operated both to lock the sails in reduced extension, and to resume the position of maximum extension corresponding to the lower values of flow intensity.

Remote control can be achieved by means - of the usual type and structure for a person skilled in the art, and therefore not described in greater detail - incorporated in the drives of devices 16, 18, 19 and 20 and which respond for example with radio controls; in this case the reduction of the sails can take place simultaneously on all the sails of the system.

Alternatively, it is however possible to provide control means placed on the end pylons of the system, in particular near the return wheels 2, 2a, and which act on the drives of the devices 16, 18, 19 and 20 electrically. or magnetic, at the moment of passage of the single sails on said return wheels 2, 2a; in this case the reduction of the sails will occur, sail by sail, only in the moment of the respective change of tack.

At the same time, although said snap couplings 19, 20 keep the position of the shank 5 'and respectively the attachment point of the sheet 8 fixed, the momentary increases in flow velocity must nevertheless be able to produce a further controlled elastic extension of both the wind surfaces. 4 and of the sheets 8. To make this extension possible, elastic resistance means are provided between the tang 5 'and the shaft 5 and respectively between the reel 17a and the stop 18, for example in the form of a spiral spring 21, with one end connected to the shank 5â € ™ and the other to the shaft 5, and a spiral spring 22 with one end fixed to the spool 17 and another end fixed to the disc 18â € ™ of the coupling 18.

According to yet another variant of execution - also represented in fig. 6 â € “It is also possible to guide the sheet 8 inside the hollow shaft 5 (as shown in the lower right part of fig.

6) and hook it to a plate 23, able to slide inside the shaft 5 in contrast to a cylindrical spring 24.

Naturally, both in the case of the spool 17 with spring 22 and in the case of the plate 23 with spring 24, these structures will be provided at both ends of the mast 5, to hook the two sheets 8 of the preceding sail.

The equipment described in its main components is analyzed below in the individual constituent components, in order to better define the protection area, thus allowing to outline any alternative and equivalent solutions.

The choice of providing two parallel catenaries is primarily determined by the fundamental function of guiding the wind surfaces more effectively and at the same time easier, so as to obtain better support for the sails, and to allow greater extension in width and in height of the flow invested. Furthermore, as can be easily understood, such a structure is capable of powering a greater number of generators. In addition to this, such a provision is aimed at solving some problems related to the system: in this way it is in fact possible to periodically replace the ropes using a single catenary for the launch of the new one, and guarantee the best use. ropes, which have structural strength limits, over time.

Each catenary has the corresponding wheels also cantilevered with the relative bearing axes fixed on support structures in such a way as to give field to the free rotation of the wind surfaces, which will rotate in the space included within the two parallel planes containing the wheels. The support wheels of the catenary rotate under the friction of the rope and are connected mechanically or hydraulically to move the electric generators.

As you can easily understand from the brief description above, so that it is possible to obtain, for the same energy of the flow invested, the maximum useful traction, parallel to the ropes, of the aerodynamic force, and therefore the best performance of the system, the surfaces 4 wind turbines must have:

a) the maximum useful dimension, compatible with the length and strength of the rope and the diameters of the wheels;

b) maximum efficiency, with the choice of the most advantageous airfoils, being able to vary the incidence of the flow even in the event of storms;

c) the maximum speed of translation tolerable with the stresses that insist on them, including those caused by accelerations when the motion is reversed on the wheels

d) reversibility, that is the equal towing capacity in both directions of motion on the catenary, as well as in relation to a possible inversion of the wind flow;

e) lightness, especially in the case of large sections.

Although they have the above characteristics, the selected and developed wind surfaces of the present invention are particularly simple, light, stable and efficient sails.

To obtain further advantages, it is possible to make some arrangements to the system according to the invention that improve performance and facilitate long-term management, as indicated below.

The rotation of the luff and the spools can take place by the action of an electrically, hydraulically or pneumatically operated clutch, for the duration and size of the selected winding.

Since the efficiency of the type of sail used directly determines the power of the system, it can be envisaged to modify its morphology and properties, for example in the way shown very schematically, in plan, in figures 7 to 9, so as to approach the efficiency of the most valid airfoils such as the rigid airfoils.

Fig. 7a shows the use of a pair of sails, mounted on two respective masts briefly spaced, which take on two different but cooperating profiles. It should be noted that both sails are held by their respective sheets in a position inside the respective leech. This way of retention allows, as already seen in figure 9a, to form the part of the sail closest to the leech in semi-rigid material, with the advantage of a more regular flow of the wind W

Figs. 7b and 7c show the use of several sheets for each sail: it is in fact known that, with two sheets fixed on a tubular luff, it is possible, by means of a slight rotation of the luff and the differentiated tension of the sheets, to deform a like the airfoil. The same two sheets can adapt to flows of different intensity, up to an almost total reduction due to storms.

Observing fig. 8, which shows the enlarged detail of fig. 7c relating to a three-ply sail, it can be noted that such a sail structure can allow correct convexity: the first two plies are in depression, thanks to the action of hole A, and under pressure due to the work of the hole B between the intermediate sheet and the lower external one. In this way an airfoil is formed with the lower convexity under pressure and the necessary convexity of the upper surface aspirated to form an asymmetrical but reversible airfoil.

It has in fact been found that in the case of a sail with three sheets, if the extrados were neglected, it would tend to become a symmetrical airfoil. However, the presence of the extrados tends to bring back the depression on the intermediate sheet, and consequently to make the sail dissymmetrical, making it concave and therefore forming an airfoil.

By leveraging the pressure of the entry angle and the depression of the extrados, depending on the direction, a wing profile is therefore obtained for the aspiration of the extrados on the essentially symmetrical part determined by the other two sheets. Thanks to the existence of the intermediate sheet, the extrados being under pressure, the part blown under pressure tends to be sucked upwards and become concave. In this way, the incoming part is kept blown in and the outgoing part acts as a wind resistance vane, allowing to obtain a self-stable wind surface that always offers an optimal flow resistance surface.

It is understood that the wind power plant thus created perfectly achieves the desired purposes. It is economical, easy to install and relatively modest maintenance, and is particularly suitable for its installation in areas where the wind is uni-directional and extended, even if alternating, such as in valleys, between ridges opposed.

With a similar solution, it is also possible to avoid the positioning of numerous poles, as is instead necessary for the propellers, and to reduce the number of poles limited to the couple needed to support the end wheels, which keep the catenaries.

It is also understood that in this way, even if there were variations in the speed of breezes or baric or seasonal and unidirectional winds, only small variations in the angles of incidence of the relative wind would be necessary.

If the valleys are long enough, several plants according to the invention can be positioned along the lateral reliefs at different and higher altitudes, where the flow is faster, and at suitable distances where the flow on a plant is not disturbed by the effect of upstream systems (see overview of fig. 1).

From studies carried out on the subject, it was found that the power that can already be obtained from the single wind energy generator object of the present invention - typically having two series of wind surfaces that are 30 meters high, for the length of a kilometer - we can attest to around 15 MW, considering a flow speed of 10 m / sec, with an expected output of 500 Watt / m <2>.

It is understood that the above description relates to a particularly preferred embodiment of the invention and that multiple modifications are possible, without departing from the scope of the invention itself, as defined by the following claims. In particular, it is possible to provide a different shape of the towing surfaces, for example a semi-elliptical shape.

Claims (6)

CLAIMS 1) Wind power plant, consisting of at least two endless ropes (1, 1a), each forming two respective catenaries substantially parallel to each other and which run around two return wheels (2, 2a), positioned reciprocally distance on supports (3) anchored to suspension pylons (P), to each of said ropes (1, 1a) being anchored to wind power surfaces (4) subject to the action of the wind, characterized by what - said wind surfaces (4) consist of sails, in flexible material, which can be rolled up on themselves, - the leading edge or luff (5) of each sail is held taut between a first pair of hooking elements (6, 6a), provided respectively on one (1) and on the other rope (1a), - the trailing edge or leech (7) is held taut by sheets (8), which branch off from said leech (7) and which hook onto a second pair of hooking elements (6, 6a), also constituting hooking elements of a subsequent sail in the direction of advancement of the ropes, - and from this that first winding means (13,14,15) are associated with each pair of fastening elements (6, 6a), to wrap each sail around to its luff, and second winding means (17, 17a), for winding each sheet (8) of a sail that precedes in the direction of advancement of the ropes. 2) Wind power plant as in claim 1), characterized by what said coupling elements (6,6a) of each pair are each fixed to a respective rope (1, 1a) in positions that correspond to each other on a vertical alignment and at distances reciprocal equal on the length of the ropes (1, 1a). 3) Wind power plant as in claims 1) or 2), characterized in that said coupling elements (6,6a) of each pair include a fixed part (9, 10), rigidly anchored on one of the ropes (1, 1a), and a joint part (11) with a substantially horizontal axis, a respective end of the luff (5) of the sail being anchored to this joint part. 4) Wind power plant as in claims 1) or 3), characterized in that said first means for furling a sail (13,14,15) comprise means (14,15) for transforming the rotation movement of each coupling element ( 6, 6a) along a respective return wheel (2, 2a) in a rotational movement of said joint (11). 5) Wind power plant as in claim 4), characterized by what said joint (11) comprises a horizontal pin (13), rotatable within a hole (10b) formed in said fixed part (10,10a) of each coupling element (6 , 6a), and a pair of bevel gears (14, 15) to transmit the rotation of the pin (13) to a vertical luff shaft (5). 6) Wind power plant as in claim 5), characterized in that a first bevel gear (14) is mounted freely rotating on said pin (13) and is associated with stop means (16) able to lock it on said fixed part ( 10,10a), and a second bevel gear (15), in meshing with said first bevel gear (14), is keyed on an extension (5â € ™) of the luff shaft (5) 7) Wind power plant as in claims 1) or 3), characterized by what said second winding means, for winding the sheet (8) of a sail (4), comprise a winding reel (17), integral with the mast luff (5) of a sail that follows in the direction of advancement of the ropes (1, 1a). 8) Wind power plant as in claims 1) or 3), characterized by what said second winding means, for winding the sheet (8) of a sail (4), comprise a winding reel (17â € ™), rotatably mounted on said pin (13) of the joint (11), associated with stop means (18) adapted to lock it on said pin (13). 9) Wind power plant as in any one of the preceding claims, characterized by what said sheets (8) are anchored to the leech in an internal point of the sail, at a distance from the edge of the leech itself. 10) Wind power plant as in claim 9), characterized in that the part of the sail comprised between said attachment points of the sheet (8) and said edge of the leech is made of a semi-rigid material. 11) Wind power plant as in any one of the preceding claims, characterized in that said return wheels (2, 2a) of the ropes (1, 1a) for transporting the sails are oriented according to sub-vertical planes, parallel and at least briefly spaced apart. 12) Wind power plant as in claim 11), characterized by the fact that the support arms (3) of the deflection wheels (2, 2a) are mounted cantilevered on said pylons and support the respective wheels on opposite external sides of the wheels themselves a free space is formed between the mutually facing inner sides of said wheels for the passage of the sails when changing their tack.