GB2396190A

GB2396190A - Controlled pitch turbine

Info

Publication number: GB2396190A
Application number: GB0229253A
Authority: GB
Inventors: Roger Green
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-12-13
Filing date: 2002-12-13
Publication date: 2004-06-16
Also published as: GB0229253D0

Abstract

A turbine in which the pitch of the blades 1 varies as the turbine rotates. The pitch is governed by the angle of the blade arm 2. The blades pitch is such that there is always a positive rotational vector produce from a linear force when the turbine is directed to that force. For a given rotational direction of the turbine, the blades rotate in their axis the opposite direction and at half the rate. This is achieved using belts and pulleys 3,4,5. The turbine can follow a change in wind direction by adjusting the central pulley. Under high wind conditions the turbine can operate at lower efficiency by pointing away from the wind thus still producing power.

Description

23961 90

Controlled Pitch Turbine My invention relates to a Turbine which controls the pitch of the blades as it rotates around its axis.

The invention is concerned with turbines that change the angle of incidence ofthe blades with respect to wind or fluid direction as they rotate, maximising the power to the turbine. The turbine will be able to operate at low wind (or fluid) speeds and at high speeds and does not require a gearbox.

The invention will now be described further with reference to the accompanying drawings in which: Figure I shows the vertical elevation (as seen from the top).

Figure 2 shows the way the angles of the blade varies around the turbine axis (as seen from the top) igure 3 shows the side view There are three blades 1. Each blade is able to rotate and is pivoted in the vertical axis to a main structure 2. I he main structure comprises ofthree arms each at 120 degrees from each other. The arms contain bearings that hold the blades. There is an upper arm and a lower arm directly under the upper one. The blades each have a belt and pulley system 3,4,5 that connects them to a 'normally stationary' pulley in the centre. The ratio ofthe centre pulley to the blade pulley is such that as the main structure and arms rotate in any given direction then the blades rotate in a counter direction but at halfrate eg: if the main structure rotates 360 degrees clockwise then the blades would have rotated 180 degrees anti- clockwise. This arrangement allows the blades to always produce a positive rotational vector to a given linear vector when the centre pulley position is adjusted accordingly. The centre pulley is able to optimise the rotational vector produced from a linear vector by maintaining the correct blade angles of incidence with respect to the linear force. For a given wind (or fluid) direction, the blades are at 45 degrees when the main structure arm points into the direction. At 90 degrees they are at 90 degrees (giving maximum rotational force), at 180 degrees they are at-45 degrees and at 270 degrees they are at O degrees (giving minimal rotational force). This can be seen in figure 2. If the wind changes direction then the centre pulley is rotated until this effect is achieved.

The wind direction is detected by weather vane 6. This is mounted to a plate that is attached to the central pulleys. The plate contains a number of detectors 7 (mechanical switches or optical devices) that detect the position of the weather vane with respect to the central pulleys. There are wires 8, that travel down the centre of the structure that send signal about the direction of the weather vane to a control unit 20. The control unit controls the motor 10 that rotates the centre pulleys via belt 9 and shaft I I.

There are three central pulleys 13, one for each blade 15. They are connected via belt 12 to the blade pulleys 14. The belt and pulleys are toothed and tensioned so as not to slip and remain in step at all times. lithe blades are connected to the main structure 19 via arms. On each arm (upper and lower) there are bearing that allow the blades to rotate about their vertical central axis.

Power from the turbine is derived from a pulley 16 and belt 17 that connects to a generator 18. The pulley 16 is large with respect to the generator pulley so as to negate the need for a gearbox as the generator is required to rotate much faster than the turbine.

During large wind speeds the unit will still be able to operate by adjusting the central pulley so as it is no longer optimum. This will stop the turbine from excessive over spin and keep it generating power from the wind. The control unit is responsible for detecting excessive wind speeds and making this adjustment.

The turbine can easily be expanded by making the blades larger. Making them taller is more efficient than wider as there will be a larger resistance to turning with wider blades.

However the turbine can easily be constructed to generate more power and torque by increasing the number of blades on each arm. The blades would just daisy chain along the arm with additional pulleys and belts. The same ratio from central pulley to blade pulley would need to be achieved for each blade.

The turbine is able to harness power from wind or fluid Row. It could also be used to generate a linear force from a rotational one. In such a system, the generator would be replaced by a motor. An example application would be the drive for a submersible where it would be possible to use such system and negate the need for a rudder and a gearbox, the system would provide controllable thrust any chosen 2 dimensions.

Claims

Claims

I. A turbine that adjusts the pitch ofthe blades with respect to incidence wind direction to optimise the power from the wind.
9. A turbine according to claim 1 wherein the pitch ofthe blades always produces a positive rotational vector in the required rotational direction to a given linear wind vector.
3. A turbine according to claim I and 2 wherein the blades are connected via a belt and pulley system in such a way a the blades rotate in the opposite direction to the turbine at halfthe rate ofthe turbine keeping the blades in such a fashion as to in claim 2
4. A turbine according to claims I to 3 that is able to adjust the angle of incidence at a given point of all the blades with respect to wind direction.
5. A turbine according to claim 4 that uses a controller and motor to achieve this effect.
6. A turbine according to claims 4 and S that uses a weather vane and direction sensors to determine the wind direction and uses this information to adjust the blade pitches.
7. A turbine according to claims 1 to 6 that detects excessive wind speeds and causes the turbine to reduce its efficiency by not operating at the optimum setting.
8. A turbine according to claims I to 3 that can increase the number of blades along each turbine arm using the same method of pulleys and belts and retains the same ratio between central pulley and each blade pulley.
9. A turbine according to claims 1 to 8 that can be used in fluid flow or wind.
10. A turbine according to claims I to 9 that can be made as a drive by using a motor to generate a rotational force that generates a linear force by the turbine.