The present invention pertains to the field of energetics and can be used in wind power plants that generate electric power through the use of air flow force.

Wind power plants are known that comprise a loop belt or chain with a plurality of blades arranged thereon, first and second shafts parallel to each other, where the blades are designed to collect wind flow energy and to set a generator in motion that converts wind energy into electrical energy. These types of wind power plants are used to convert wind energy into electric energy in industry, such as used by power companies, as well as for household purposes and in vehicles, e.g. for moving ships. One such a device is described in the Georgian patent GE P 2015 6273 B, which contains an endless flexible belt that is stretched between two pulleys, with blades mounted the belt, the blades axes on both sides fixed in cylindrical bearings mounted on adjacent belt sections. Stop washers are attached to the axes from the end face to restrict the rotation of the blades.

The disadvantage of the above described device is its relatively low efficiency, which is caused by the non-optimal absorption of wind energy by the blades. In particular, at low wind speeds, such as 3-4 m/s, the moment from the center of gravity of the blade, which is shifted from the axis of the blade to its end, prevents the blade from occupying the position determined by the opening restrictor under the influence of wind. At intermediate wind speeds and under fixed blade rotation angles, the optimum belt speed (in terms of the plant efficiency factor) varies in proportion to the wind speed, making it difficult to select and adjust the plant generating electrical load. At high wind speeds, such as speeds above 20 m/s, the centrifugal force acting on the pulley becomes inadmissible in terms of calculating blade strength. The forces acting on the supports of the plant also become inadmissible.

The technical result of this invention is the increase of energy utilization efficiency. The wind power plant according to the present invention comprises a rotatable drive belt that forms an endless loop with a set of spaced apart blades, and is rotatably mounted on the outer surface of said drive belt and is designed to receive wind energy, wherein each blade of the set of the blades is mounted on a shaft with the capability of rotating about its axis; an electric generator operably connected to the drive belt and designed to generate electrical energy as a result of the movement of the drive belt; the plant also comprising a plurality of adjusting devices for adjusting the rotation angle of each blade, wherein each adjusting device containing two support members having upper and lower ends, wherein the lower ends are fastened to the outer surface of the belt; lifters fastened to the support members, eccentric discs at the ends of the blade shaft that have a predetermined profile and being put on and fastened to the blade shaft, a spring element, with its ends attached to the upper ends of the said support members in such a manner that the said lifters by the force of tension of said spring element make frictional contact with said eccentric disc; the eccentric disc, lifters and spring element are configured in such a manner that a moment of pressing force is transmitted to the blade shaft, which determines the angle of rotation of the blade and its orientation towards the wind flow.

This technical result is achieved by optimally changing the angle of inclination of the blades with respect to the wind flow. In particular, as mentioned above, the plant is provided with a blade orientation adjustment device, which is embodied as a camshaft mechanism mounted on both ends of each blade shaft.

Thus, in the process of operating using the camshaft mechanism, the blades of the plant change their orientation optimally with respect to the direction of the wind flow.

The present invention is explained by the appended figures, wherein:

Fig. 1 is a schematic representation of an endless drive belt with blades attached to it;

Fig. 2 shows a schematic illustration of a device for attaching a blade to a drive belt and adjusting its rotation;

Fig. 3 shows a schematic representation of an eccentric disc;

Figures 4a-b show schematic illustrations of the blade.

Fig. 5 shows a schematic illustration of the damping device; Fig. 6 shows a blade shaft mounted on a drive belt.

Fig. 7 depicts a perspective view of the wind power plant according to the present invention. Referring to Fig. 1, the plant comprises an endless flexible belt 1 which is stretched between two pulleys 2, 3, one of which 2 is mounted on supports (not shown in the figure), while the other 3 ismounted at a ground level and is functionally connected to an electric power generator (not shown in the figure) designed to generate electric energy as a result of movement of the belt by wind energy. Blades 4 are mounted on the endless belt 1. As can be seen from fig. 1, the blades are attached to the parallel branches of the belt, on their outer side, with the capability of turning the blades in the direction of the wind. Besides, the wind direction should be perpendicular to the axis of the pulleys of the blades. Passing through the first branch of the belt transmission from the outer side, the air flow will cause the second, opposite branch to blow down from the inside and turn the blades at the opposite angle, but the force will always be directed towards the front of the blade in the belt motion direction.

In the proposed structure, it is also possible to use a chain instead of a belt. Despite the fact that the belt of the plant illustrated in fig. 1 is shown with the capability of moving in the vertical direction, in case of using the chain, the latter can also be moved horizontally.

As is well known, wind speed is not constant over time and depends on geographical location. Wind installations become profitable when the average cubic value of wind speed exceeds 6-8 m/s. When each element of the blade has occupied a certain angle with respect to the axial flow of the air, it gains force that has axial and tangential components under the influence of this flow. The smaller this angle is, the greater the axial component is and the smaller the tangential component is that creates the useful moment on the shaft. In the plant according to the present invention, each blade is provided with an adjusting device that changes the angle of inclination of the blade with respect to the wind.

Fig. 2 shows a schematic representation of a device for attaching a blade to a belt and adjusting its rotation in a lateral view. The mentioned device comprises supports 3 mounted on a drive belt 1 by means of fasteners 2, to which roller lifters are attached. The lifters 4 are pressed against the eccentric disc 5 of the camshaft mechanism, which is put on and attached to the blade shaft 6. The ends of the spring element 7 are attached to the upper ends of the supports 3. Fasteners 2 in this structure are made of a resilient material, such as rubber, so that the supports 3 are capable of moving via the spring elements 7 and press the lifters 4 against the eccentric disc 5.

According to the present invention, the use of a camshaft mechanism became possible due to the fact that the moment of force generated on the shaft by the wind pressure is quite small and it is possible to balance the camshaft mechanism with a spring 7 in order to reach the balance. Besides, in the proposed technical solution, two lifters 4 are placed opposite each other with respect to the eccentric disc5 of the camshaft mechanism, which are pressed against the eccentric disc 5 from two sides by the force of the spring element 7 by means of the two supports 3. In this case the lifters 4 are acted upon by the force from the spring element 7 in the direction of the eccentric disc5. Thus the eccentric disc 5 and the lifters 4 are frictionally connected to each other. All the above elements, namely the eccentric disc, lifters and spring element are positioned in such a manner that the pressing moment is transmitted to the blades and the position of the latter is subject to control. Thus, when the wind speed reaches a certain value, the blade starts to rotate and assumes a position that is determined by the profile of the eccentric disc.

The adjusting device is configured in such a manner that the power of the wind power plant remains substantially constant when the wind speed exceeds a specific value.

The profile of the eccentric dischavs different radii along the circle, and in areas where the radius is increased, the spring element 7 is more tensioned when the lifters 4 are pressed. Selection of spring 7 and eccentric disc 5 profiles is made taking into account the specific location conditions and wind strength. Below, the specific calculated parameters considering specific local conditions are given as an example. In particular, fig. 3 shows a schematic representation of the eccentric disc with operating zones separated in its profile. The figure shows the projecting areas of the disc profile to the right and left hand sides, which correspond to increments of different sizes of the disk radius. The first zone is the zone in which the wind speed is less than 3.5 m/s and is deemed to be a non working zone. In the figure, this zone is defined for the first (straight) branch of the drive belt between points 0 and 1, and for the second (backward-moving) branch - between points 0 and 5. The angle of inclination a = 0° of the blade with respect to wind at point 0, and at point 1 - a = 24.5°. As for the point 5 for the second branch, in it a = -26.4°. The increments of the eccentric disc radius in points 1 and 5 with respect to the radii at point 0 are Ar = -0,012 mm and Ar = 0.04 mm, respectively.

The second zone, which is a working zone, is in the range of wind speeds 3.5 m/s - 15.7 m/s. This zone is defined for the first branch as the section between points 1 and 2 at which a = 31.8 ⁰ and the radius increment Ar = 1.14 mm, and for the second branch - as the section between points 5 and 6 at which a = -39.1 °, and the increment of the radius Ar = 3.63 mm. The optimal mode of operation of the wind power plant is maintained in this zone in terms of efficiency factor, during which the maximum power is withdrawn from the wind. At this time, the speed of movement of the belt increases slightly.

After that the non-working mode begins, the blades rotate exactly in the direction of the wind and take the position of the minimum frontal resistance. At point 3 a = 90°, Ar = 1.5 mm, at point 7 a = -90 °, Ar = 4 mm. At this time, the wind pressure force increases slightly and through the above structure the wind power plant will be able to withstand even very strong hurricane winds.

In the embodiment at issue, the initial radius of the eccentric disc is rO = 11.5 mm (point 0) and the blade is installed along the belt. It is clear that under the initial radius conditions, the spring element must be stretched and in this case its stretching starts at a radius r = 10 mm. In this case, the spring tension coefficient is equal to 0.125 n/mm, i.e. a rather weak spring is used.

In other words, the rotation of the blades starts from the neutral position, when the blade cords are directed along the belt and their nose is set in the direction of movement of the belt.When coming out of the neutral position, the blades in the first and second branches of the belt rotate in different directions. The eccentric disc and lifters can be made of different materials, depending on the magnitude of the forces in the device. Steel or steel alloys as well as molded materials, plastics, etc. can be used for this purpose.

The spring element in this case can preferably be made in the form of a spiral compression spring; however, other types of spring elements or flexible elements, such as flat springs, etc. can also be used.

Possibility of rotation of the disc disk under the compressive impact of the spiral spring, also the use of roller lifterscauses slight friction wear and at the same time the adjusting device will have a high degree of control.

Each of the blades in the plant has a shape that changes its aerodynamic profile and/or area. For this purpose, the blade can have a complex aerodynamic profile.

The optimal area of the blades can be selected taking into account the specific wind conditions. Figures 4a-b show schematic illustrations of the blade.

For optimal operation of the machine, the end portion 1 of the blades can be made of lightweight foam, which will be hermetically sealed with the film surface 2 of the blade. Thus the so-called air-filled vessel is created, in which the pressure increases during bending under the influence of wind and, as a result, its hardness increases. In addition, due to the displacement of air in the "vessel", the blade acquires damping properties to suppress vibrations.

The efficiency of the plant is affected by undesirable attenuated oscillations that occur when the blades rotate from one position of equilibrium to another, which is due to the presence of inertia in the structure. Obviously, the longer these oscillations are, the lower is the efficiency of the plant.

In order to solve the above problem, the present invention proposes a damping device, which is shown in fig. 5. The damping device contains a cylindrical tube 1 which is put on and attached to a blade shaft 2. On the mentioned tube, fine-pored spongy rubber 3 (with open pores) is glued. Conventional rubber tape 4 is glued on top of the spongy rubber 3. Track rollers 5 with the axes attached to two adjustable supports 6 are attached to the tube from two sides. The supports 6 with their fastening elements 7 are attached to the drive belt 8. When the shaft 2 rotates, the track rollers start rolling on the spongy rubber and air flows through it through thin pores. The supports are adjusted by drawbar9. With such a structure, the higher the rotational speed of the shaft, the greater the resistance to rotation.

Fig. 6 shows a blade lwith a shaft 2 mounted on a drive belt 3. The shaft 2 passes through the above-mentioned oscillation suppression device 4 and the above-mentioned blade rotation regulator 5.

Referring to fig. 7, a perspective view of the wind power plant according to the present invention is depicted, wherein the reference numerals to designate a variety of the elements of the structure are the same as those illustrated in fig. 1.