GB2473881A

GB2473881A - Shielded, self regulating transverse wind or water turbine

Info

Publication number: GB2473881A
Application number: GB0917070A
Authority: GB
Inventors: David Wilson
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-09-29
Filing date: 2009-09-29
Publication date: 2011-03-30
Also published as: GB0917070D0

Abstract

A free fluid turbine comprises a shaft mounting plural, e.g. three, radial blades 14 for rotation in response to fluid force acting thereon and a first deflector or shield 16. The first deflector has an outer profile joining leading and trailing edges to at least partially surround an outer surface of a first upstream quadrant of a circumference defined by rotation of the blades. The leading edge deflects fluid flow to facilitate blade rotation and creates a low pressure within the first quadrant to assist blade return. A diametrically opposed second deflector 18 fixed relative to the first deflector also guides flow. The deflectors are aligned to flow by a fin 20 sized so that excess wind causes to second deflector to overcome the fin and rotate the first deflector upstream of the rotor. The shaft may be rigid and materials lightweight.

Description

Fluid Powered Turbine Assembly The present invention relates to a fluid powered turbine assembly and, in particular but not exclusively, to a wind or water powered turbine assembly.

The detrimental effects on the environment of the use of fossil fuel for the generation of energy have led to an ever growing interest in the use and development of devices capable of capturing energy from renewable energy sources.

Renewable energy sources are of interest because they are largely naturally occurring and sustainable, and hence cause minimal detrimental effect to the environment and, theoretically at least, provide an inexhaustible source of energy.

Renewable energy power generation includes the utilisation of wind power, water power, solar energy, waste water and biofuels, for example.

A growing source of renewable energy is wind power.

Wind power is usually generated by means of a wind turbine which converts the kinetic energy in the wind into mechanical energy which is then converted to electricity.

Wind turbines are generally classified based on the axis in which the turbine rotates i.e. horizontal-axis wind turbines (HAWT5) or vertical-axis wind turbine (VAWTs).

HAWTs have a main rotor shaft and an electrical generator positioned at the top of a tower and must be pointed into the wind. In large turbines, this is generally achieved by means of a wind sensor coupled with a servo motor. Small HAWTs frequently use a simple wind vane to point them in the required direction.

A disadvantage with a large HAWT is that a massive tower construction is required to support the components of the turbine and due to the nature of its size, it is difficult to transport from the manufacturing plant to a site for installation.

In addition, maintenance of the mechanical components of a large HAWT can be hazardous as access is required to the turbine mounted at the top of the tower which can be up to 90 meters tall.

Furthermore, the tower of a HAWT needs to be at least twice the height of the blades thus limiting the number of suitable locations a HAWT can be positioned.

VAWT5 overcome the above problems associated with traditional horizontal designs and offer improved performance while also delivering significant benefits to businesses.

VAWT5 have the main rotor shaft arranged vertically. In addition because they do not require a massive tower structure, they are more frequently mounted nearer the ground than a HAWT.

A key advantage of a VAWT is that, depending on the design, it does not need to be pointed into the wind to be efficient. Another advantage of the VAWTs is that they are more accessible for maintenance than a HAWT since the mechanical components can be place near the ground.

Most VAWT5 produce energy at a much lower efficiency than that of a HAWT in large part due to the additional drag they have as their blades rotate into the wind.

Various designs have been proposed in the art to increase the efficiency of VAWT5. For example, US4850792 discloses a vertical axis wind turbine which includes a pair of wind deflectors for directing the wind current into the rotor assembly. US5375968 discloses a wind turbine with a rotor assembly provided with a plurality of wind-drivable blades and surrounded by a rotatable wind deflector assembly.

According to the invention there is provided a fluid powered turbine assembly comprising a shaft; a plurality of blades adapted to rotate in response to a fluid force acting thereon, the blades being mounted on the shaft; and a first deflecting means having an outer profile, the first deflecting means having a leading edge and a trailing edge, and being configured to at least partially surround an outer surface of a first quadrant of a circumference defined by rotation of the blades extending radially from the shaft, wherein the leading edge of the first deflecting means is arranged to deflect the direction of a fluid flow to facilitate rotation of the blades and further to creates a low pressure area within the first quadrant of the circumference defined by rotation of the blades extending radially from the shaft.

Thus, in use, when the shaft is positioned perpendicular to the direction of fluid flow, the first deflecting means will be positioned in a path of fluid flow upstream from the shaft.

The invention provides an improved turbine assembly arrangement to that of the prior art. Unlike the prior art, as disclosed in US4850792 and US5375968, the arrangement of the invention does not require the utilisation of deflectors designed to deflect oncoming wind onto the blades so as to optimize the efficiency of the turbine.

The creation of a low pressure area i.e. a reduced pressure area, within the first quadrant of the circumference defined by rotation of the blades extending radially from the shaft results in the pulling of the blades in the direction of rotation as the assembly seeks to equal ise the pressure differential created by the first deflecting means.

In addition, by having the first deflecting means positioned in the path of fluid flow upstream from the shaft, the first deflecting means acts as a barrier against the oncoming fluid resulting in a reduction in drag caused by the blades having to rotate against the wind.

Preferably the first deflecting means comprises a substantially curved outer profile.

The length of the shaft would be dependent on the size of the turbine assembly.

Preferably the shaft comprises a rigid material. The rigid material may be any suitable material, for example, the shaft may comprise stainless steel, reinforced fibre glass, aluminium etc. The shaft may be a solid shaft or a hollow shaft.

In exemplary embodiments of the invention, the shaft is a drive shaft.

Preferably the assembly comprises three blades equally spaced apart from each other around the shaft and extending radially therefrom. Thus, the blades are spaced apart from one another at an angle of 120 degrees.

Preferably the length of an axis of the blades parallel to a longitudinal axis of the shaft is substantially equal in length to the longitudinal axis of the shaft.

The blades may be rotatably mounted on the shaft. Alternatively, the blades may be fixedly mounted on the shaft and the shaft and blades rotate on bearings.

In exemplary embodiments, the blades comprise a planar surface profile.

In other exemplary embodiments, the blades comprise a curved surface profile.

The advantage of the blades each having a curved surface profile is that the blades would occupy less space than a blade with a planar surface profile while maintaining the same surface area. In addition, a curved surface profile will mean that the blade will be less resistant to fluid flow on one side that the other which will facilitate rotation of the blades.

Preferably the blades comprise a lightweight material. The use of a lightweight material for the blades means that a lesser fluid force would be required to cause the blades to rotate than if the blades comprised a heavy material. More specifically, the blades comprise a plastics or fabric material.

Preferably the first deflecting means comprises a lightweight material.

More specifically, the first deflecting means comprises a lightweight weather resistant material. The lightweight weather resistant material may be any suitable material known in the art, for example a lightweight weather resistant plastics material.

Preferably the length of an axis of the first deflecting means parallel to a longitudinal axis of the shaft is substantially equal in length to the longitudinal axis of the shaft.

Preferably the first deflecting means surrounds the outer surface of the first quadrant of the circumference defined by rotation of the blades extending radially from the shaft.

Preferably the blades are adapted to rotate in a direction opposite the direction from the leading edge of the first deflecting means to the trailing edge of the first deflecting means.

Preferably the turbine assembly further comprises a second deflecting means. It is preferred that the second deflecting means has a substantially curved outer profile having a leading edge and a trailing edge, and is configured to at least partially surround an outer surface of a second quadrant of the circumference defined by rotation of the blades extending radially from the shaft Preferably the second quadrant is diagonally disposed from the first quadrant. Thus in use, the second deflecting means will be positioned so as to be in a path of fluid flow downstream from the shaft.

Preferably the second deflecting means comprises a lightweight material.

More specifically, the second deflecting means comprises a lightweight weather resistant material. The lightweight weather resistant material may be any suitable material known in the art, for example a lightweight weather resistant plastics material.

Preferably the length of an axis of the second deflecting means parallel to a longitudinal axis of the shaft is substantially equal in length to the longitudinal axis of the shaft.

Preferably the second deflecting means surrounds the outer surface of the second quadrant of the circumference defined by rotation of the blades extending radially from the shaft.

Preferably the turbine assembly further comprises an orientation means.

The orientation means may comprise a vane having a longitudinal axis perpendicular to the longitudinal axis of the shaft.

Alternatively the orientation means may comprise a vane having a longitudinal axis parallel to the longitudinal axis of the shaft.

The orientation means is made from a suitable material, for example, the orientation means may comprise a plastics material, a metallic material or a fabric material. In preferred embodiments of the invention, orientation means is made from a fabric material such as KEVLAR.(RTM) The first deflecting means, second deflecting means and orientation means move and are in fixed positions relative to each other but these three units move as one but independently of the blades.

Due to the fact that the first deflecting means, second deflecting means and orientation means move as one and independently of the blades, the turbine assembly would respond quicker to changes in fluid direction that a HAWT as the whole unit does not need to be pointed into the path of fluid flow.

The orientation means ensures that the first and second deflecting means are always in the correct position relative to the direction of fluid flow to ensure maximum performance of the turbine assembly. The blades will always rotate in the same direction regardless of the direction of fluid flow.

As fluid passes across the blades of a VAWT, a force will act against the blades causing them to rotate. When an increase in the speed of fluid flow occurs, an increase in fluid force acting on the blades occurs causing the blades to rotate at a higher speed. In adverse conditions, the speed of rotation of the blades due to the resultant increase in fluid force acting thereon is greater than its designed tolerance, leading to damage to the blades and a reduction in the efficiency of the VAWT.

Preferably the orientation means is located in a predetermined position relative to the second deflecting means. By having the orientation means in a predetermined position relative to the second deflecting means, the turbine assembly can be self regulating.

In use, the orientation means positions the first and second deflecting means in the correct position relative to the direction of fluid flow. As fluid passes across the turbine assembly, a force will act against the second deflecting means inclining it to move in a direction relative to the direction of rotation of the blades. Up to a certain speed of fluid flow, the force acting on the orientation means is greater than the force acting on the second deflecting means thus maintaining the first and second deflecting means in the correction position relative to the direction of fluid flow.

When an increase in the speed of fluid flow occurs, an increase in fluid force acting on the second deflecting means occurs. When the force acting on the second deflecting means increases past the point where it results in an unfavourable rotational speed of the blades, the force acting on the second deflecting means would surpass the force acting on the orientation means. This would cause the first deflecting means, second deflecting means and orientation means to rotate in a direction towards the direction of rotation of the blades. As they rotate, the first deflecting means would move into the path of fluid flow acting on the blades to cause them to rotate creating a partial barrier against the oncoming fluid resulting in a reduction in rotational speed of the blades.

In exemplary embodiments of the invention, the turbine assembly is a wind powered turbine assembly.

In exemplary embodiments of the invention, the turbine assembly is a water powered turbine assembly.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

There now follows a description of a preferred embodiment(s) of the invention, by way of non-limiting example, with reference being made to the accompanying drawings, in which: Figure 1 shows a first embodiment of a fluid powered turbine assembly according to the invention; Figure 2 shows a partial perspective view of the fluid powered turbine assembly of figure 1 with the blades removed; Figure 3 is a plan view of an arrangement of a first and second defecting means according to a first embodiment of a fluid powered turbine assembly according to the invention; Figure 4 shows an embodiment of a shaft and blade arrangement for a fluid powered turbine assembly according to the invention; Figure 5 is a plan view of the fluid turbine assembly of figure 1 when positioned in the path of fluid flow; and Figures 6 and 7 show a second embodiment of a fluid powered turbine assembly according to the invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Further, although the invention will be described in terms of specific embodiments, it will be understood that various elements of the specific embodiments of the invention will be applicable to all embodiments disclosed herein.

In the drawings, similar features are denoted by the same reference signs throughout.

Referring to figures 1 to 5, a first embodiment of a fluid powered turbine assembly 10 according to the invention is shown.

The turbine assembly comprises a shaft 12 (figure 4); a plurality of blades 14 connected to the shaft 12 and being adapted to rotate with the shaft on bearings 28 in response to a fluid force acting thereon; a first deflecting 16 means having a substantially curved outer profile; a second deflecting 18 means having a substantially curved outer profile and orientation means adapted to orientate the turbine assembly 10 relative to a direction of fluid flow.

The shaft 12 is made from a rigid material, such as stainless steel and comprises a weather resistant outer coating.

The blades 14 are fixedly mounted on the shaft 12; and have an axis perpendicular to a longitudinal axis of the shaft 12. The blades 14 have a length substantially equal in length to the longitudinal axis of the shaft 12.

In other arrangements of the first embodiment of the invention, the blades 14 extend along a section of the shaft 12 rather than substantially along the length of the shaft 12.

The blades 14 are mounted on the shaft such that they have an edge which is proximate the first deflecting means during rotation.

In the embodiment shown, the turbine assembly 10 comprises three blades 14 equally spaced apart from each other at an angle of 120 degrees around the shaft 12. While the turbine assembly 10 is shown to have three blades 14, it is to be understood that the turbine assembly 10 may comprise two blades or, indeed, more than three blades.

The blades 14 comprise a planar surface profile. In alternative embodiments of the invention, not shown, the blades 14 comprise a curved surface profile.

The blades 14 are made from a lightweight plastics material, however they may be made from any lightweight material suitable for the environment of use.

The first deflecting means is an aerofoil 16 having a leading edge 24 and a trailing edge 26, and is positioned so as to be in a path of fluid flow, i.e. wind or water flow, upstream from the shaft 12 and is adapted to surround an outer surface a first quadrant of a circumference defined by rotation of the blades 14 extending radially from the shaft 12 (see figure 3).

While the aerofoil 16, is shown to surround the first quadrant, it is to be understood that the aerofoil 16 may only partially surround the first quadrant.

The second deflecting means is a compressor 18 having a leading edge 30 and a trailing edge 32, and is positioned so as to be in the path of wind/water flow downstream from the shaft 12. The compressor 18 is adapted to surround an outer surface of a second quadrant of a circumference defined by rotation of the blades 14 extending radially from the shaft 12 diagonally disposed from the first quadrant (see figure 3).

The aerofoil 16 and compressor 18 each comprise an axis parallel to the longitudinal axis of the shaft 12 which is substantially equal in length to the length of the shaft. It is to be understood that it is not essential for the axis of the aerofoil 16 and compressor 18 parallel the longitudinal axis of the shaft 12 to be substantially equal in length to the length of the shaft. It is only necessary for the axis to be equal or greater than the length of the blades 14.

The aerofoil 16 and compressor 18 are made of a lightweight weather resistant material and are both connected to the bearings 28 by means of connecting struts.

The orientation means is in the form of a vane or fin 20 mounted on one of the connecting struts 22. The fin 20 is made from a lightweight fabric material such as KELVAR.(RTM) The aerofoil 16, compressor 18 and fin 20 move and are in fixed positions relative to each other. The three components move as one but independently of the blades.

The blades 14 are adapted to rotate in a direction opposite the direction of a path from a leading edge 24 of the first deflecting means 16 to a trailing edge 26 of the first deflecting means 16.

The turbine assembly 10 will now be described for use as a wind turbine, with particular reference to figure 5. Please note that the fin 20 has been omitted from figure 5 to improve its clarity. The turbine assembly 10 may be connected to a generator as known in the art in order to convert the mechanical energy generated by the turbine assembly 10 into electricity.

Alternatively, the turbine assembly may be connected directly or indirectly to another device which harnesses the mechanical energy generated by the turbine assembly 10 to provide mechanical energy for operating the device.

In use, the shaft 12 is positioned relative to the wind direction such that rotation of the blades can be actuated by wind flowing across the turbine assembly. Preferably the shaft 12 is positioned perpendicular to the wind direction. However, the shaft 12 may be positioned substantially perpendicular or offset from the wind direction. As wind 34 flows past the fin 20, if the fin 20 is not aligned with the wind direction, the wind 34 will act on the fin 20 and move it so that it is aligned in the wind direction. As the fin 20 aligns itself with the wind 34, it will orientate the aerofoil 16 and compressor 18 such that the leading edge 24 of the aerofoil 16 is in line with the trailing edge 32 of the compressor 18. Due to the location of the aerofoil 16, i.e. upstream the shaft 16, as wind 34 flows across the turbine assembly 10 it will only come into contact with the blades 14 having a surface exposed to the wind 34 i.e. the blades not being shielded from the wind by the aerofoil 16. In the situation shown in figure 5a, the wind 34 will engage with blade 14a but not blades 14b and 14c as they are being shielded from the wind 34 by the aerofoil.

As the wind comes into contact with the blade 14a, a force is exerted against the blade surface which results in the rotation of the blade 1 4a and hence rotation of the shaft 12 and remaining blades 14b, 14c.

As the blades rotate, the blade 14a moves into the second quadrant, the ensuing blade 14c leaves the first quadrant while the advance positioned blade 14b remains shielded from the wind 34 by the aerofoil 16. As the blade 14c leaves the shielding of the aerofoil 16, one of its surfaces will become exposed to the wind 34 and the force of the wind 34 will cause it to rotate, hence rotating the other blades 14 and the shaft 12.

As can be seen in figure Sb, at certain positions during rotation of the blade, the wind 34 is come into contact with two blades 14 (blades 1 4a and 14c in figure Sb). Because of the alignment of the blades 14 from each other, the wind 34 will always engage with a surface of at least one blade 14.

In addition with the wind 34 engaging with the blades 14, it will come into contact with an inner surface of the compressor 18. Due to the curved profile of the compressor 18, the wind will be deflected towards the trailing edge 32 of the compressor 18. The deflected wind will come into contact with the surface of a blade 14 located within the second quadrant applying a rotational force to the blade 14 thus facilitating rotation of the blades.

The amount of wind 34 deflected by the compressor 18 will be dependent on the position of the blades 14. For example, the amount of wind 34 defected when the blades are in the position shown in figure 5b will be greater than when the blades are in the position shown in figure 5a because a greater surface area of the compressor 18 will be exposed to the oncoming wind 34.

The rotation of the blades 14 is further facilitated by the aerofoil 16 which creates a low pressure area i.e. a reduced pressure area, within the first quadrant. As a blade enters the low pressure area, a pulling force is exerted on the blade in the direction of rotation as the turbine assembly 10 seeks to equalise the pressure differential created by the first deflecting means.

The design of the fin 20 should be such that apart from positioning the aerofoil 16 and compressor 18 in the correct position relative to the direction of fluid flow, it provides means for self regulating the turbine assembly 10 in adverse conditions.

As mentioned above, when the wind 34 passes across the turbine assembly 10 it will come into contact with the compressor 18. The wind 34 generates a force that acts against the compressor 18 inclining it to move in a direction relative to the direction of rotation of the blades 14. Up to a certain wind speed, the force acting on the vane is greater than the force acting on the compressor 18 and as such the aerofoil 16 and compressor 18 are moved into or maintained in the correction position relative to the wind direction for optimal efficiency. When an increase in the wind speed occurs, an increase in the rotational speed of the blades 14 and in the force acting on the compressor 18 occurs.

If the rotational speed of the blades 14 increases beyond their designed tolerance, the blades will get damaged resulting in reduced efficiency of the turbine assembly 10.

The fin 20 is designed such that when the speed of the wind acting on the compressor 18 increases past a point where it begins to result in an unfavourable rotational speed of the blades 14, the force acting on the compressor 18 surpasses the force acting on the fin 20. When the force acting on the compressor 18 is greater than the force acting on the fin 20, the fin 20 can no longer prevent movement of the compressor 18 due to the force acting on it. As a result the compressor 18 will rotate in the direction of rotation of the blades 14 (see figure 5c). Since the aerofoil 16, compressor 18 and fin 20 are in fixed positions relative to each other, rotation of the compressor 18 will also result in rotation of the aerofoil 16 and fin 20. As units rotate, the aerofoil 16 would move into the path of the wind 34 acting on the blade 14a (see figure Sc). The aerofoil 16 acts as a barrier and partially shields the surface of the blade 14a resulting in a reduction in the surface area of the blade 14a exposed to the oncoming wind. A reduction in the surface area of the blade 14a exposed to the wind means that a reduced wind effect occurs such that the rotational speed of the blades will decease due to less force acting on the blades than when the aerofoil is orientated for optimal efficiency as shown in figures 5a and Sb.

Further rotation of the aerofoil 16, as shown in figure Sd, will result in the blades 14 having to rotate into the wind 34 which will create additional drag and further slow the rotation of the blades.

When the wind speed has reduced to a level within the tolerance of the turbine assembly 10, the force acting on the compressor 18 will be less than the force acting on the fin 20 and the fin 20 will realign the aerofoil 16 and the compressor 18 in the position shown in figure 5a.

Referring to figures 6 and 7, a second embodiment of a turbine assembly 100 according to the invention.

Like the first embodiment, the turbine assembly 100 comprises a shaft, a plurality of blades 14 connected to the shaft 12, a first deflecting means 16 in the form of an aerofoil, and orientation means 120 adapted to orientate the turbine assembly 100 relative to a direction of fluid flow.

The shaft 12 and aerofoil 16 are the similar in construction to that of the first embodiment and will not be described in any further detail.

The second embodiment differs from the first embodiment in that the second embodiment does not comprise a second deflecting means and in that the orientation means is in the form of a tail 120 positioned perpendicular to the shaft 12.

The tail 120 is made of a lightweight fabric material such as KELVAR M) is connected to the bearings by connecting struts 122. The aerofoil 16 and the tail 120 are in fixed positions relative to each other and the two components move as one but independently of the blades 14.

The blades 14 may be connected directly to the shaft 12 as in the first embodiment or may be connected to the shaft by means of connectors 102 as shown in figures 6 and 7.

The blades 14 are made from a lightweight plastics material and have an axis perpendicular to a longitudinal axis of the shaft 12. The blades 14 have a length substantially equal in length to the longitudinal axis of the shaft 12 and are adapted to rotate within the boundaries defined by the connecting struts 122.

While the invention has been described with particular reference to use as a wind turbine, it should be understood that the invention can be powered by an alternative fluid, for example water.

Furthermore, while the first deflecting means has been described a having a substantially curved outer profile, the first deflecting means may be of an alternative shape or configuration which will create an area of low pressure within the first quadrant of the circumference defined by rotation of the blades extending radially from the shaft. In such an arrangement, the blades and the first deflecting means require to be positioned proximate each other so that as the blades rotate, an edge of the blades passes through the area of low pressure.

Claims

Claims 1. A fluid powered turbine assembly comprising a shaft; a plurality of blades adapted to rotate in response to a fluid force acting thereon, the blades being rotatably mounted on the shaft; and a first deflecting means having an outer profile, the first deflecting means having a leading edge and a trailing edge, and being configured to at least partially surround an outer surface of a first quadrant of a circumference defined by rotation of the blades extending radially from the shaft, wherein the leading edge of the first deflecting means is arranged to deflect the direction of a fluid flow to facilitate rotation of the blades and further to creates a low pressure area within the first quadrant of the circumference defined by rotation of the blades extending radially from the shaft.
2. A turbine assembly according to claim 1 wherein the first deflecting means comprises a substantially curved outer profile.
3. A turbine assembly according to claim 1 or claim 2 wherein the shaft comprises a rigid material.
4. A turbine assembly according to any one of the preceding claims wherein the assembly comprises three blades equally spaced apart from each other around the shaft.
5. A turbine assembly according to any one of the preceding claims wherein the length of an axis of the blades parallel to a longitudinal axis of the shaft is substantially equal in length to the longitudinal axis of the shaft.
6. A turbine assembly according to any one of the preceding claims wherein the blades are rotatably mounted on the shaft.
7. A turbine assembly according to any one of claims 1 to 6 wherein the blades are fixedly mounted on the shaft and the shaft and blades rotate on bearings.
8. A turbine assembly according any one of the preceding claims wherein the blades comprise a planar surface profile.
9. A turbine assembly according to any one of claims 1 to 7 wherein the blades comprise a curved surface profile.
10. A turbine assembly according to any one of the preceding claims wherein the blades comprise a lightweight plastics material.
11. A turbine assembly according to any one of the preceding claims wherein the first deflecting means comprises a lightweight plastics material.
12. A turbine assembly according to any one of the preceding claims wherein the length of an axis of the first deflecting means parallel to a longitudinal axis of the shaft is substantially equal in length to the longitudinal axis of the shaft.
13. A turbine assembly according to any one of the preceding claims wherein the first deflecting means surrounds the outer surface of the first quadrant.
14. A turbine assembly according to any one of the preceding claims wherein the blades are adapted to rotate in a direction opposite the direction of the leading edge of the first deflecting means to the trailing edge of the first deflecting means.
15. A turbine assembly according to any one of the preceding claims further comprising a second deflecting means.
16. A turbine assembly according to claim 15 wherein the second deflecting means has a substantially curved outer profile having a leading edge and a trailing edge, and is configured to at least partially surround an outer surface of a second quadrant of the circumference defined by rotation of the blades extending radially from the shaft.
17. A turbine assembly according to claim 16 wherein the second quadrant is diagonally disposed from the first quadrant.
18. A turbine assembly according to any one of claims 15 to 17 wherein the second deflecting means comprises a lightweight plastics material.
19. A turbine assembly according to any one of claims 15 to 18 wherein the length of an axis of the second deflecting means parallel to a longitudinal axis of the shaft is substantially equal in length to the longitudinal axis of the shaft.
20. A turbine assembly according to any one of claims 15 to 19 wherein the second deflecting means surrounds outer surface of the second quadrant.
21. A turbine assembly according to any one of the preceding claims further comprising an orientation means.
22. A turbine assembly according to claim 21 wherein the orientation means comprises a vane having a longitudinal axis perpendicular to the longitudinal axis of the shaft.
23. A turbine assembly according to claim 21 wherein the steering means comprises a vane having a longitudinal axis parallel to the longitudinal axis of the shaft.
24. A turbine assembly according to any one of the preceding claims wherein the turbine assembly is a wind powered turbine assembly.
25. A turbine assembly according to any one of claims 1 to 24 wherein the turbine assembly is a water powered turbine assembly.