VERTICAL-AXIS WIND TURBINE

The present invention relates to the vertical-axis wind turbines with movable blades.

Wind turbines are particularly used for the production of electricity. As the tendency towards environment-friendliness and therefore to clean energy is enhanced in recent years, the wind turbines progressively gain importance and develop rapidly. Now, the power of an average wind turbine is around 1MW.

Wind turbines are classified in two groups, namely : the horizontal-axis wind turbines and the vertical-axis wind turbines. The horizontal axis wind turbines which consist of a high tower with a generator and three blades on it, are more commonly used. Said wind turbines have to be turned to the direction of the wind. The wind impact onto the inclined surfaces of the turbine blades, forces said blades to rotate in a direction that is 90° reverse to its direction. These blades rotating in different directions are also the source of undesired turbulences. The active areas facing the wind are small, i.e the blade surfaces are narrow (as compared to the swept area in order to get rid of said turbulence. However, a device operating by means of the wind power is expected to meet the wind at larger areas, as is the case for the sails of a vessel.

Vertical-axis wind turbines are developed to increase the areas facing the wind, of the wind turbines, and therefore to increase their efficiencies as well as to eliminate the obligation to turn them towards the wind.

In US Patent No. 4377372, a wind turbine wherein a plurality of blades are used at the same rotational level, is disclosed. This excessive number of blades cause reverse reflections and preventions of each other's wind. In the US^-Patent No. 5808369, blades opening and closing in four directions, which are placed only at the ends of the pair of supporting arms, catch the wind as a box but as they do not allow the used wind to exit and be discharged, wind overflowing from the top or bottom of the blade, interferes with the flow of the wind towards the top or bottom blade.

Any system operated by the wind power is first of all, expected to have a perfect aerodynamic structure whereas this consideration is overridden in almost all vertical-axis wind turbines of the prior art; said vertical axis wind-turbines all have very detailed and dispersed mechanisms. The turbines are intended to be operated with winds at optimum speed but they may also be exposed to wind storms. Keeping a force under control is as important as bringing it out. The fact that the areas facing the wind in the horizontal-axis wind turbines are smaller, may be advantageous to a certain degree, with respect to protection against storms.

Anyhow, narrow blades of the horizontal axis turbines are taken under protection by means of the pitch control function; however in systems with larger areas exposed to wind, protection is more important.

The object of the present invention is to realize a more efficient vertical-axis wind turbine with means for controlling the rotation/speed and a storm protection system.

The vertical-axis wind turbine with storm protection, realized to attain the above mentioned object of the invention, has been illustrated in the attached drawings, wherein :

Figure 1, is the general view of the vertical-axis wind turbine, Figure 2, is the view showing the mutually opposing two blade assemblies

Figure 3, is the section-view of the blade assembly in open position Figure 4, is the section- view of the blade assembly in closed position Figure 5, is the section-view of the blade assembly in semi-open position Figure 6, is the section view of an alternative embodiment with double hinge shaft,

Figure 7, is the general view of the vertical-axis wind turbine with frame- type blades.

The components shown in the drawings are given reference numerals as listed below:

1. vertical-axis wind turbine

2. support structure

3. vertical axis

4. blade assembly 5. supporting arm

6. blade

7. lower blade-upper blade compensating unit

8. hydraulic control unit

9. compensating arm 10. hydraulic cylinder

11. hydraulic cylinder piston rod

12. spring

13. compensating arms and triple joint connection of the cylinder piston rod

14. compensating arm-blade movable joint 15. hinge connecting blades to the support arm

16. compensating arm operation slot

17. pressure transmitting hose

18. frame blades

19. frame 20. double shaft - hinge The vertical-axis wind turbine (1) of the present invention consists of a vertical axis (3) mounted on the support structure (2) and the blade assemblies (4) connected onto said axis (3) horizontally in a descending order, from the top to the bottom. Said vertical axis (3) is ratable around its axis and transmits this rotary movement to such components as a generator, a motor, a pump, and the like converting it to other types of energy. The blade assembly (4) consists of an elliptical support arm (5) and two blades, namely the upper and the lower blades (6) connected to said support arm (5) by a hinge (15) and the compensating arm (9).

A compensating operation slot (16) is provided on the support arm (5) for the movement of said compensating arm (9). Another blade assembly is placed as opposed to each blade assembly (4) with respect to the vertical axis, the hinged edges (15) being in reverse direction. In other words, a pair of blade assembly (4) is provided at each level of the vertical axis (3) (fig. 1). When the turbine (1) receives the wind from its front, as the hinged edges (15) of the blades (6) at the right of the vertical axis (3) are at the back, wind filled in the blade (6) inner space from the free side, opens the blades completely. In this case, the rotating blades (6) enlargen their areas to face the wind as much as possible, while rotating in the direction of the wind; thus wind forces the blades (6) to rotate in its flow direction and by pushing the blades (6) which are limited in the opening direction to rotate the blade assembly completely. The blade (6) rotates from behind towards the front of the axis (3), at its left side and its hinged side (15) now is in the wind direction and then the blades (6) receiving the wind from behind, close on the support arm (5) and take an aerodynamic form. When rotation against the direction of the wind starts, said blades (6) make their areas exposed to wind as small as possible and come forwards against the wind by a minimum resistance. When the blades (6) at the front, pass to the left of the axis (3) from its right, they come to a semi-open position by means of the spring (12) provided on the lower blade-upper blade compensating unit (7). The blades (6), now at the right side of the axis (3) are in a semi open position to receive the wind and in this case rotation is still continuing. These opening-closing movements of the blades (6) arranged on the vertical axis (3) repeat at each rotation.

In order to improve the operation of the turbine (1), auxiliary mechanisms such as the lower blade-upper blade compensating unit (7) and the hydraulic control unit (8) are developed. The lower blade-upper blade compensating unit (7) regulates the cooperation of the lower and upper blades (6). Normally, in an environment with no winds, if the blades (6) are left as they are, the upper blade (6) falls over the support arm (5) by its own weight and closes, whereas the lower blade (6) hangs down by the gravitational force and remains open. The lower blade-upper blade compensating unit (7), consisting of the compensating arm (9), the compensating arm-blade movable joint (14), the triple-joint connection formed by two compensating arms (9) and the hydraulic cylinder rod (11), the spring (12) and a passage way wherein the triple joint connection (13) is guided in the support arm (5). The lower blade-upper blade compensating unit (7) enables two blades (6) to open/close together. Furthermore, it creates a balance by using the movement of the lower blade (6) which has a tendency to fall down, to raise the upper blade (6) upwards and thus provides a more efficient operation of the turbine (1). The spring (12) placed in the lower blade-upper blade compensating unit (7), applies a force onto the triple joint connection (13) and thus holds the blades (6) in a semi open position when there is no wind. This is particularly advantageous when the blades (6) are in a position where they are in front of the axis (3) with respect to the wind. In this case, as the blade (6) will start to open at this short time period when it is not effected by the wind, receiving of the wind into the blade during the next moment of the rotation will be accelerated.

A balancing/compensation between the opposingly arranged blade assemblies (4) is also required in addition to the balance between the upper and lower blades (6) for an efficient operation of the turbine (1). When the blades (6) of one assembly (4) are filled with wind and open, the blades (6) of the opposing assembly (4) should be closed. This movement is regulated by the hydraulic control unit (8). The pushing piston rod (11) of the hydraulic cylinder (10) placed in the support arm (5) activates the blades (6) to open or to close, by acting on the lower blade-upper blade compensating unit (7) by means of the triple joint connection (13). The hydraulic cylinders (10) of the mutually opposing blade assemblies (4) are interconnected by means of a pressure transmitting hose (17). When the blades (6) of one assembly (4) open or close, the reverse of this movement occurs in the blades (6) of the other assembly (4). During the operation of the turbine (1) by the wind, when the blades (6) of one assembly are filled with wind and open, whereas the others are completely closed by means of oil (or air) pumped by the hydraulic control unit (8). A self-closing procedure by means of the pushing force of the wind is not completely realized, whereas the closing is fully realized by the hydraulic control unit (8). Thus the wind power will not be consumed during the reverse rotation. This unit (8) is also used for controlling the speed of revolution and protecting against storm. In case extra oil is pumped to the hydraulic control unit (8), this operation narrows the opening limits of all blades (6), which in turn makes it possible to stay at the desired speed of revolution at different winds. In case the pressure applied on said unit (8) is continued, at the end of this procedure all blades (6) close entirely on the support arm (5); they are packed. With their ideal aerodynamic structures at closed position, the blades thus are taken under a perfect storm protection. The blades (6) which wind around the support arm (5) form a completely closed structure in such a manner that the wind storm causes no damages to the turbine (1).

The vertical axis (3) to which the blade assemblies (4) are connected, rotates in the bearing recess provided in the supporting structure (2) fixed to the ground. A rotation speed sensing unit in the axis (3), provides a constant rotation speed at different wind speeds by operating over the hydraulic control unit (8). While providing the rotational speed control, when the oil pressure in the hydraulic control unit (8) exceeds a predetermined level, extra oil is pumped to the system, the blades (6) are completely closed and taken under protection against storm. The open blades (6) of the turbine (1) according to the present invention, are preferably of a concave structure in the wind direction. This characteristic, causes the wind to be caught by the blades (6) and a maximum yield to be obtained from the wind power. Said concave structure extends along the entire blade (6) as a groove and both ends of the blade (6) are open. Wind, leaving its energy by its impact on the inner surface of the blade (6), leaves the blade (6) inner space by taking the benefit of said concave structure serving as a groove, in order to be replaced by the new wind. This evacuation is realized either from the inside or from the outside, depending on the angle of the blade (6) with respect to the wind. Thus, the overflow of the wind from the upper and lower sides of the blades (6) is avoided and the smooth flow of the wind towards an upper and a lower blade assembly (4) will not be disturbed.

In an alternative embodiment of the turbine (1) according to the present invention, the upper and lower blades (6) are interconnected by means of a hinge with two shafts (20) (Fig.6). The upper and lower blades (6) are connected separately by using separate shafts to the support arm (5), Furthermore said shafts (20) are elongated so that the opposing blade assembly (4) is directly connected to said hinge shafts. To realize this procedure, the sides of the blade (6) and the support arm (5), with the hinge, have to be offset towards the center of the axis (3). While connecting the upper blade (6) to the upper blade (6) and the lower blade (6) to the lower blade (6), the hinge shafts of opposing blades (6) are so adjusted that all blades (6) will stand in semi-open positions. After the connection, if one blade (6) opens completely, the blade (6) of the opposing assembly has to be closed by the shaft drive. Moreover, by the pushing of the spring (12) in the lower blade-upper blade compensating unit (7), all blades are forced to stay in a semi-open position when there is no wind. In this embodiment, the lower blade- upper blade compensating unit (7) is used but the hydraulic control unit (8) is not used. As the wind opens the blades (6) of one group, the blades (6) of the opposing assembly is automatically closed. In this embodiment with a hinge (20) with double shaft, the rotation is continuous. The turbine (1) cannot be interfered for such purposes as rotation/speed control or protection against storm, from outside. In this embodiment with simplified hinge with double shaft (20), as the blades (6) will run away in front of the wind at a speed close to that of the wind, during storm, small-types of embodiments with solid construction will not be damaged. As storm is not an important factor to be considered for the double-shaft hinge (20) embodiments, a pipe may be used instead of the elliptical supporting arm (5).

In another embodiment of the turbine (1) according to the present invention, frame blades (18) are used (fιg.7). The vertical-axis turbine (1) with frame blades (18) consists of a support structure (2), a vertical axis (3), frames (19) connected to the vertical axis (3) and blades (18) placed inside said frames (19). The blades (18) are attached to the frame (19) at their upper sections by shafts. When there is no wind, the blades (18) completely close the frame (19) under the effect of the gravitational force. However, against the wind, the blades (18) on one side of the axis (3) stay closed, while those on the other side of the axis (3) allow the wind to pass through the frame by bringing their surfaces to a position parallel to the ground. As the closed blades side will resist the wind, they are forced to rotate. The free lower edges of the blades (18) that are arranged on the frames (19) in a descending order, i.e. from the top to the bottom, are so placed that they move only at one face of the frame (19) and they are not allowed to pass to the other side of the frame (19). For this reason, the passage of the wind through the blades (18) is only uni-directional. This characteristic of the blades, convert the power of the wind to a rotary movement. In a vertical - axis turbine with frame blades, the rotation/speed control and protection against storm, are realized by bringing the blade (18) surfaces to a position parallel to the ground, by the weights escaping out under the effect of centrifugal force, that raise the free edges of said blades (18) upwards.

By the use of the wind turbine (1) according to the present invention, the wind, being out most important source of "clean energy" will not be an alternative source any more, but it will be the main source of energy. Installation costs of the wind turbines will be reduced as efficiency will increase. Fossile fuel consumption will decrease and the global calefaction will be slowed down, by using wind as the main energy source. By virtue of the vertical.-axis turbine (1) which is more efficient than a horizontal-axis turbine of the same size, the wind energy potential of the world will be enhanced.