AU1019702A - Wind motor - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT WIND MOTOR The following statement is a full description of this invention, including the best method of performing it known to me: Wind motor This invention relates to improvements of efficiency for wind motors with vertical shafts.

An important renewable energy source is the wind energy. However a considerable part of this energy is delivered in the medium to low range of the wind speeds. Current technologies using propellers have a limited efficiency in the lower range of wind speeds. The units using propellers are limited in size by the complexity of the propeller and the structural costs needed to support the weight of the electric generator at the hight of the tower. The device presented 10 below is capable of converting low speed winds and high-speed winds as well into mechanical rotation efficiently by using wings instead of a propeller. Higher output energy per unit can be achieved at lower costs and with relatively unsophisticated technologies.

One example of the invention is presented on the accompanying drawings: FIGURE 1 shows one example in using rigid aerodynamic wings for the wind motor.

FIGURE 2 shows the assembly of wind motor with the electric generator attached.

The new device for converting the wind energy into mechanical rotation is shown as a view from top with the upper plate removed in FIGURE 1. It is formed from a number of rigid aerodynamic profiled wings 2 each hinging on its own axle 3.

The axles 3 are fastened between the lower 7 and upper plate 8 and are positioned equidistant to the main shaft 1. The main shaft 1 and the axels 3 are in a vertical position. The distance between the axels is equal. Each wing 2 can rotate a certain angle around its vertical shaft 3, restricted by the position of external and internal stop 5. The wing's axis in mid position is tangent to the rotation circle, with the front of the wing pointing to the direction of rotation. From the mid position of the wing 2 the mechanical stops 5 will allow a rotation angle of 45 deg. towards the exterior or 45 deg. towards the interior of the assembly. The axle is positioned substantially towards the front of the wing. The wing completely covers the axel.

The wing is centrifugal balanced in regard to its axel (the front is heavier then the rear). When exposed to the forces of wind the wing will assume a position with the front facing the wind. As the stops are limiting the wing's movement the resulting position is shown in FIGURE 1 in different locations. Each wing 2 has a lateral flap 4 facing the exterior of the assembly that hinges on the same axle 3 and completes the aerodynamic profile of the wing when closed, as seen in DETAIL 1. The lateral flap is centrifugal unbalanced and is pushed towards the external stop by the centrifugal force. However the wind pressure prevails in determining the flap's position. A small gap or a detachment at the rear of the flap may help open the flap when the airflow reverses from tail to front.

There are four distinct situations in the way that the wing operates along the periphery of the assembly and for a better understanding of the process the periphery has been subdivided in quarters (see FIGURE 1).

In the first quarter the wing 2 and flap 4 is pushed by the wind pressure towards the internal stop and the wing generates a force in the direction of rotation. The airflow along the wing is from the front to the tail.

In the second quarter the airflow along the wing reverses and the pressure on the flap diminishes, as the axis of the wing is close to the wind direction. This leads to the opening of the flap by centrifugal forces and additional aerodynamic means caused by the reversed airflow. The flap will rest on the external stop. The wing being centrifugal balanced continues to rest on the internal stop. The resulting vprofile formed by the wing and the open flap maximises the wind energy utilisation, generating a force in the direction of rotation of the assembly.

In the third quarter the wind pressure pushes the wing and flap in closed position towards the external stop and generates a force in the direction of rotation as well.

In the forth quarter wing and flap are closed and positioned between the stops offering a minimum resistance profile to the wind. This force acts against the rotation but is substantially smaller then the other three forces.

The assembly rotates around the main vertical shaft when subjected to the forces of wind. The wings are repositioned accordingly if the wind direction changes, so that the forces generated by the wind continuously rotate the assembly in the same direction. No orientation mechanisms are necessary.

An over-speed protection has been provided in case of high wind speeds.

FIGURE 1 DETAIL 2 shows the lock 6 in a non-activated position. The fixing •25 hole 9 is above the centre of gravity of the lock. The lock is fixed flush under the lower plate by a bolt with its axes in horizontal plane and tangent to the rotation circle. In case of over-speed the centrifugal force exceeds the spring 10 tension and the lock rotates around the bolt and protrudes above the plate surface, in the *path of the wing. In this position the lock and the external stop keeps the wing i 30 from hinging freely and the speed decreases as the efficiency of the motor is compromised.

FIGURE 2 represents the assembly of the wind motor with the electric generator attached. The axels 3 are the supporting element of the upper plate 8 to the lover plate 7 forming a sort of squirrel-cage structure. The lower plate is attached to the main shaft 1. The main shaft 1 of the wind motor drives the electric generator 11 and can support the whole structure. The electric generator, which is the heaviest part in the assembly, is positioned at the lowest point, conferring the assembly a good stability. The upper plate serves as a lower plate for the tier above in a multi-tier assembly. No other structural support between the upper and lower plate interferes with the flow of air and the wings can utilise the maximum available wind energy. The minimum number of wings in one-tier assemblies is four. For large structures it is preferable to have an odd number of wings.

The assembly has one or more tiers located one above the other. The neighbouring tiers are relatively offset by an angle equal to the quotient obtained from the division of the angle between the neighbouring wings by the number of tiers.

This type of wind motor can produce mechanical energy economically in a large range: from a few KW up to tens of MW per unit. The wind motor can be used in various locations: on farms, in wind farms, on high raising buildings, on sea platforms or for the propulsion of ships.

Claims (7)

1. A wind motor with vertical shaft comprising of a number of rigid, aerodynamic profiled wings, centrifugal balanced and hinged onto their own vertical axels, each axel positioned substantially towards the front of the wing while the tail of the wing is able to rotate between two stops and the axels positioned at equal distance on a circle with the main vertical shaft in the centre.

2. The wind motor of claim 1 wherein the limitation of the wing's rotation can be modified while the motor turns, by shifting the stops to different positions, including the shifting of the stops in the opposite position, therefore reversing the turning direction of the motor.

3. The wind motor of any of the claims 1 or 2 wherein a flap is hinged on the same axle as the wing, faces the exterior of the assembly, is centrifugally unbalanced and completes the aerodynamic profile of the wing in closed position or is opened by the centrifugal force if the lateral pressure caused by the wind is les then the first one, forming a v-shape profile in conjunction with the wing.

4. The wind motor of claim 3 wherein the flap is provided with additional aerodynamic means to sense the reversing of wind flow and to accelerate i 20 the opening process.

The wind motor of any of the claims 1 to 4 wherein the vertical axels are the only structural support for the wings and connect the upper and lower plate of the motor.

6. The wind motor of any of the claims 1 to 5 wherein a over-speed lock is fitted under the lower plate with the fixing hole of the lock above it's centre of gravity, which enables it in case of over-speed, when the centrifugal force exceeds the spring's tension to rotate around the bolt and protrude above the plate surface, blocking the wing from hinging freely and in this way to reduce the rotating speed of the motor.

7. A wind motor substantially as herein described with reference to the accompanying drawings. Comeliu A. Mateevici 15 JANUARY 2002