FIELD OF THE INVENTION

The invention relates to a wind power plant. More specifically, the present invention relates to a wind power plant comprising a chamber having an inlet for an air flow, a plurality of blades arranged on an endless belt or chain inside the chamber, a first shaft and a second shaft arranged in parallel to the first shaft, wherein the blades are arranged to collect energy from an airflow flowing in through the inlet and by at least one of the first shaft and the second shaft and the belt or chain drive a generator to convert energy from the incoming airflow to electric energy. Wind power plants of this type are used for converting wind power to electric energy and can be used both within industry, such as electric companies and other producers of electricity, and consumers, such as households and other consumers. For example, this type of wind power plants can be used to provide residential buildings and industries with electric power. This type of wind power plants can also be used on ships or vehicles to produce electricity for propelling the ship or vehicle. Further, the present invention relates to a method for converting wind power to electric power.

PRIOR ART

There is a plurality of different types of wind power plants in the prior art. One common type of wind power plants comprise a wind turbine arranged in a top portion of a tower. The wind turbine comprises a horizontally arranged shaft and a plurality of blades arranged around the shaft, which blade are rotated around the horizontal shaft by means of an airflow passing the wind power plant, wherein kinetic energy of the airflow, which is also called wind energy or wind power, is converted into electric energy by means of a generator. Common wind power plants of this type further comprise a gear to increase the rotation speed for standard-type generators. To direct the wind turbine towards the wind usually an electric or hydraulic yaw drive is used. For example, the operation is automatic by means of computer equipment, which starts the wind power plant when the wind is sufficient and stops it when there is a storm or malfunction. To stop the wind turbine generally a combination of mechanic and

aerodynamic brakes are used.

Another type of known wind power plants comprise a plurality of blades arranged on an endless loop belt or chain to receive the wind and rotate a shaft for driving a generator.

Despite a variety of different types of wind power plants there is a need to further improve and make the harvesting of electric power from wind power more efficient. One problem with prior art wind power plants is that they are expensive and that large plants are often required to keep the costs for production of electricity at low levels. As a result it is difficult to use prior art wind power plants for production of household electricity, for example, at the direct site of the user or consumer. Another problem with prior art wind power plants is that they can cause negative effects on the environment as the often have moving parts visible from a large distance and thus can be disturbing the view of the landscape.

One drawback with some types of prior art wind power plants is that they are exposed to considerable wear.

Another drawback with this type of wind power plants is that the efficiency is low.

SUMMARY OF THE INVENTION

One object of the invention is to avoid the drawbacks and problems of prior art. The invention results in a more efficient extraction of energy and a reliable wind power plant of this type having long endurance.

The present invention relates to a wind power plant comprising a chamber having an inlet for an air flow, a plurality of blades arranged on an endless belt or chain inside the chamber, a first shaft and a second shaft arranged in parallel to the first shaft, wherein the blades are arranged to receive energy from an airflow flowing in through the inlet and through the belt or chain drive the first shaft and the second shaft and a generator connected to at least one of the first shaft and the second shaft to convert energy from the incoming airflow to electric energy, characterised in that the first shaft and the second shaft are arranged substantially vertically, and that the blades are arranged with a bowl-shaped upper portion and a lower portion, wherein the bowl-shaped upper portion is formed with a curved surface to provide lifting force in a direction perpendicular a running direction of the belt or chain. The vertical arrangement of the shafts in combination with the shape of the blades to drive the belt or chain in a substantially horizontal plane and at the same time provide a lifting power on the blades results in an efficient and visually discrete wind power plant having long endurance. The blades can be formed as wings having an angle of attack and/or a curved outer surface to provide the lifting power. Possibly, the blades can also be formed with a curved inner surface, so that an upper bowl-shaped portion extends beyond an lower portion of the blades to provide lifting power. The lifting power provided through the shape of the blades results in reduced friction as the blades and the belt or chain are rotated around inside the chamber. For example, any friction between the blades and the inside of the chamber can be reduced. Further, any friction between the belt or chain and construction parts around which the belt or chain run around can be reduced by the provided lifting power.

The chamber can be elongated and arranged with a first inlet in a first end portion to supply a first airflow to a first part of the chamber, and can be formed with a second inlet in an opposite second end portion to supply a second airflow to a second part of the chamber. Hence, airflows can be conducted into opposite end portions of the wind power plant to drive opposite pars of the belt or chain through the blades and provide more efficient drive thereof.

The wind power plant can comprise a tapered, such as conical, funnel-shaped or similar, tube element to collect a larger amount of air from the wind and guide it to the inlet or inlets. Hence, an efficient supply of airflow to the inlet or both the first inlet and the second inlet, which can be arranged to supply airflows into the chamber in different directions, is achieved.

The present invention is also related to a method for converting wind power to electric energy, comprising the steps of

a) conducting an airflow to a chamber through an inlet,

b) conducting the airflow to a plurality of blades arranged on an endless loop belt or chain and thereby driving the belt or chain in a running direction,

c) rotating a first shaft arranged vertically and connected to the belt or chain, and a second shaft arranged in parallel to the first shaft,

d) by rotating at least one of the first and second shaft driving a generator to convert energy from the airflow to electric energy, and

e) conducting the airflow to a bowl-shaped upper portion of the blades and thereby provide a lifting power in a direction perpendicular to the running direction of the belt or chain while the airflow is driving the belt or chain in the running direction by means of the blades.

Additional features and advantages of the present invention are evident from the description of embodiment examples below, appended drawings and dependent claims.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will now be described more in detail by means of embodiment examples and reference to the appended drawings, in which

Fig. 1 is a schematic view from above of a wind power plant according to one embodiment of the present invention, wherein the wind power plant is illustrated without generator,

Fig. 2 is a schematic section view of the wind power plant of Fig. 1 , illustrating blades arranged on a belt or chain inside a chamber for receiving wind power to drive a first shaft through a first pulley and a second shaft through a second pulley, Fig. 3 is a schematic side view of the wind power plant according to Fig. 1 , illustrating the wind power plant without generator, Fig. 4 is a schematic section view of a part of the wind power plant of Fig. 3,

Fig. 5 is a schematic section view of a part of the wind power plant of Fig. 3, illustrating a blade according to one embodiment,

Fig. 6 is a schematic section view of a system comprising a plurality of wind power plants according to one embodiment, and

Fig. 7 is a schematic section view of a system comprising a plurality of wind power plants according to one embodiment.

THE INVENTION

With reference to Fig. 1 a wind power plant 10 is illustrated schematically according to one embodiment. The wind power plant 10 is arranged to extract energy from wind power, such as by conversion of kinetic energy of an airflow to electric power by means of a generator. The generator is not illustrated in the drawings. For example, the generator is a conventional generator. For example, the wind power plant 10 is arranged to be used for producing household electricity or for producing electric power to ships or vehicles.

The wind power plant 10 comprises a chamber 11 . The chamber 11 is arranged as a closed loop tube, which in the illustrated embodiment is elongated to form a first end portion 12 and an opposite second end portion 13. For example, the chamber 11 is arranged as an elongated closed loop having U-shaped end portions 12, 13 and two parallel straight tube portions 14, 15 between them. Alternatively, the chamber 11 is arranged with an oval shape seen from above. The chamber 11 is configured to be arranged in a lying position and extend in a substantially horizontal plane. For example, the chamber 11 is formed in metal, such as sheet metal. Alternatively, the chamber 11 is arranged in plastic materials.

The chamber 11 is formed with at least one inlet for conducting an airflow into the chamber 11 . In the illustrated embodiment, the wind power plant 10 is formed with a first inlet 16 and a second inlet 17. The inlets 16,

17 are arranged in opposite portions of the chamber 11 . For example, the first inlet 16 is arranged at the first end portion 12, wherein the second inlet 17 is arranged at the second end portion 13. In the illustrated embodiment, the first inlet 16 is arranged at the first end portion 12 and displaced towards one of the straight portions 14, wherein the second inlet 17 is arranged at the second end portion 13 and displaced towards the opposite straight tube portion 15. For example, the first inlet 16 is arranged to conduct an airflow to one of the straight tube portions 14, wherein the second inlet 17 is arranged to conduct an airflow to the second straight tube portion 15 in the opposite direction.

The wind power plant 10 comprises a conical tube element 18 to collect wind and guide it to at least the first inlet 16 or to both the first and second inlets 16, 17, as illustrated in the drawings. The tapered tube element 18 is arranged to collect the wind from an area being substantially bigger than an area of the first inlet 16 and the second inlet 17 and then conduct the collected airflow to the inlets 16, 17. For example, the tapered tube element 18 is arranged at an end portion of the chamber 11 , such as the first end portion 12. Alternatively, the tapered tube element 18 is arranged at a long side of the chamber 11 . In the illustrated embodiment, the tapered tube element 18 is connected to the first inlet 16 through a substantially straight tube and to the second inlet 17 through a tube having a substantially straight tube portion 19 extending in parallel to the chamber 11 and a U-shaped tube portion 20. For example, the tapered tube element 18 is adapted to be arranged straight towards the wind, which is illustrated in Fig. 1 by means of the arrow V, for collecting it. The wind power plant further comprises a first shaft 21 extending vertically and a second shaft 22 arranged in parallel to the first shaft 21 . The first shaft 21 and/or the second shaft 22 is connected to the generator (not illustrated in the drawings) for driving it. The shafts 21 , 22 are in the illustrated embodiment arranged outside the chamber 11 but extend into the space enclosed by the loop-shape of the chamber 11 . The shafts 21 , 22 are partially arranged between the end portions 12, 13 of the chamber and between the straight tube portions 14, 15 of the chamber 11 . In the illustrated embodiment, the first shaft 21 is connected to a first pulley 23, wherein the second shaft 22 is connected to a second pulley 24. The pulleys 23, 24 partially extend into the chamber 11 through openings arranged in a wall of the chamber 11 .

With reference to Fig. 2 the wind power plant 10 comprises a plurality of blades 26 arranged on an endless belt or chain 25. The blades 26 are arranged inside the chamber 11 and are arranged for receiving the airflow conducted to the chamber 11 to drive the shafts 21 , 22 through the pulleys 23, 24 and the belt or chain 25. The blades 26 are distributed along the belt or chain 25 and are, for example, fixed to it. Hence, the blades 26 run in a track around the pulleys 23, 24 in an endless loop formed by the belt or chain 25. Alternatively, the belt or chain 25 run directly around the shafts 21 , 22. As illustrated schematically in Fig. 2, a first portion of the airflow collected by the tapered tube element 18 is conducted to one of the straight tube portions 14 of the chamber 11 , which first portion of the airflow is illustrated by means of the arrow V1 , wherein a second portion of the airflow collected by the tapered tube element 18 is conducted to the other straight tube portion 15 of the chamber 11 , which second portion of the airflow is illustrated by means of the arrow V2. The first portion of the airflow V1 is guided into the chamber 11 through the first inlet 16 to move the blades 26 along one of the straight tube portions 14 and thereby drive the belt or chain 25 in a first direction around the shafts 21 , 22, which first direction is counter-clockwise in Fig. 2.

Simultaneously, the second portion of the airflow V2 is guided to the second inlet 17 to move the blades 26 in the second straight tube portion 15 in the first direction around the shafts 21 , 22 in a direction towards the first inlet 16. Hence, the portions of the airflow V1 , V2 are brought into the chamber 11 from opposite directions and to different portions of the chamber 11 to drive the blades 26 around the shafts 21 , 22 in the same direction, such as counter-clockwise.

With reference to Fig. 3 the chamber 11 is illustrated from the side. The chamber 11 is arranged substantially horizontally and the tapered tube element 18 is arranged for collecting wind in the form of a

substantially horizontal airflow, which is illustrated in Fig. 3 by means of the arrow V. The shafts 21 , 22 extend perpendicular from a longitudinal direction of the chamber 11 and from an imaginary horizontal plane in the longitudinal direction of the chamber 11 . In the illustrated embodiment the shafts 21 , 22 extend vertically upward, wherein at least one of the shafts 21 , 22 is connected to the generator. Alternatively, at least one of the shafts 21 , 22 extend downward for connection to the generator.

Fig. 4 is a schematic section view from the side of the chamber 11 , wherein the blades 26 in the second straight tube portion 15 are illustrated. The blades 26 in the second straight tube portion 15 are driven by the incoming airflow in a direction illustrated by means of the arrow A. Hence, the blades 26 are driven in a horizontal direction in a horizontal plane in the track around the shafts 21 , 22 formed by the chamber 11 . The blades 26 in the second straight tube portion 26 are primarily driven by the airflow coming in through the second inlet 17, wherein the blades 26 in the first straight tube portion 14 primarily are driven by the airflow coming in through the first inlet 16 in a direction opposite the arrow A, so that the shafts 21 , 22 are driven in a rotational direction through the pulleys 23, 24 and the belt or chain 25.

With reference to Fig. 5 a blade 26 arranged in the chamber 11 is illustrated from the side. The blades 26 are arranged for collecting the airflow introduced into the chamber 11 , so that the blades 26 are driven in the direction of the airflow, which is illustrated schematically by means of the arrow B in Fig. 5. Hence, the blades 26 are formed to collect a substantially horizontal airflow H and thereby be moved in a horizontal direction. The airflow can be linear or turbulent. Further, the blades 16 are arranged to provide lifting power, which is illustrated schematically by means of the arrow C in Fig. 5. For example, the blades 26 are arranged with a bowl-shaped upper portion 27 and a lower portion 28, wherein the bowl-shaped upper portion 27 extends beyond the lower portion 28 for receiving a portion of the airflow to provide lifting power. For example, the blades 26 are formed as wings to provide lifting power. For example, the upper portion 27 of the blades 26 are formed with a curved outer surface, so that air flowing passed the blades 26 will have a longer distance to pass along the upper portion 27 of the blades 26 than the lower portion 28 of the blades 26 to provide a lifting power in a corresponding manner as a wing, which is illustrated schematically by means of the arrows D and E in Fig. 5. For example, the blades 26 are arranged with an angle of attack to the airflow to provide a lifting power. Flence, the blades 26 are arranged to be driven forward by the airflow brought into the chamber 11 and at the same time be pushed or lifted upward to reduce friction between the blades 26 and an inside of the chamber 11 and/or reduce friction between the belt or chain 25 and pulleys 23, 24 or shafts 21 , 22 and/or reduce friction between the belt or chain 25 and an inner side of the chamber 1 or a guide or similar for the belt or chain 25. The blades 26 are arranged with a shape to provide a lifting power on the blades 26 through the airflow inside the chamber 11 , which lifting power is directed vertically upwards to reduce friction losses inside the chamber 11 when the blades 26 are driven around inside the chamber 11 while driving the belt or chain 25, the pulleys 23, 24 and the shafts 21 , 22. For example, the bowl-shaped upper portion 27 of the blades 26 are arranged so that it projects beyond an outer end of the lower portion 28 in a direction towards the direction of the airflow and in a direction opposite a running direction of the blades 26. For example, the bowl-shaped upper portion 27 is formed with a curved inner surface, which is curved in a vertical plane and extends substantially from a horizontal upper end portion to a substantially vertically extending portion connecting to the lower portion 28 while the curved inner surface of the bow-shaped upper portion 27 is curved also in a horizontal plane and is at least partially U-shaped in a horizontal direction.

With reference to Fig. 6 a system for converting wind power to electric power is illustrated according to one embodiment, wherein a plurality of wind power plants 10a, 10b, 10c are connected to each other through the first shaft 21 and the second shaft 22. Each of the wind power plants 10a-c are, for example, arranged as the wind power plant 10 described above. Hence, the first shaft 21 and the second shaft 22 are driven by a plurality of wind power plants 10a-c. For example, the shafts 21 , 22 are in common for the wind power plants 10a-c. At least one of the shafts 21 , 22 is connected to a generator 29. In the illustrated embodiment the first shaft 21 is connected to a first generator 29, wherein the second shaft 22 is connected to a second generator 29. The wind power plants 10a-c are aligned, displaced in the vertical direction in relation to each other and extend in parallel to each other in a horizontal direction. Such a system can comprise any number of wind power plants 10.

With reference to Fig. 7 an alternative embodiment of a system for converting wind power to electric energy is illustrated schematically, wherein a plurality of wind power plants 10d-I as described above are connected to each other through at least one mutual shaft 21 , 22. For example, the first shaft 21 of one wind power plant is connected to the second shaft 22 of the immediate next wind power plant above or below. Hence, the wind power plants 10d-h in the illustrated embodiment are arranged in horizontal rows, which alternatingly are displaced in the horizontal direction.

With reference to Fig. 8 a wind power plant 10 is illustrated, which is attached to a base 30 according to one embodiment. The base 30 is arranged to be positioned on or be fixed to a bedding, such as underlying ground. The wind power plant 10 is rotatable around a vertical axis 31 on said base 30, so that the wind power plant 10 can be turned according to current wind direction V. For example, the base 30 is connected to a rod received in a pipe to form a rotatable connection between the wind power plant 10 and the base 30 around the vertical axis 31 . In the illustrated embodiment the wind power plant 10 is connected to a plate 32 to force the tapered tube element 18 of the wind power plant 10 towards the wind direction V, so that the wind power plant 10 is turned continuously by means of the wind to guide the airflow into the tapered tube element 18 of the wind power plant 10. For example, the plate 32 is elongated and extends in a vertical plane in the longitudinal direction of the wind power plant 10, such as between the first shaft 21 and the second shaft 22. For example, the generator 29 is arranged in an end of the wind power plant 10 opposite the tapered tube element 18 or at the second shaft 22.