GB2303409A

GB2303409A - Turbine

Info

Publication number: GB2303409A
Application number: GB9514850A
Authority: GB
Inventors: Derek Alan Taylor; David John Sharpe
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-07-20
Filing date: 1995-07-20
Publication date: 1997-02-19
Anticipated expiration: 2015-07-20
Also published as: GB2303409A8; GB2303409B; GB9514850D0

Description

A TURBINE FOR EXTRACTING POWER FROM FLUID FLOWS SPECIFICATION Technical field This invention relates to a famiiy of rotary devices or turbines designed to extract power from fluid flows by aerodynamic means. These are principally cross-flow devices but can also function as axial flow devices. These devices can in particular extract power from winds, air streams, river currents, ocean currents, and tidal currents.

Background The majority of conventional wind turbines are horizontal axis axial flow devices which have to have their axis of rotation aligned with the wind direction in order to function. Vertical axis wind turbines are cross-flow wind turbines in which the wind flow approaches the turbine largely at 90 degrees to the axis of rotation. Vertical axis cross-flow wind turbines can function with the wind blowing from any compass direction.

This invention is a derivative of the invention described in Patent No. GB 2102079 B invented by Dr Derek Taylor. This invention differs from that invention in a number of ways. These differences are principally in the number and positions of the balance weights and also the ability to teeter (as described below) in which the rotor is neutrally stable when stationary and positively stable when rotating with the centre of gravity of the rotor acting at or close to the z axis of the rotor.

Essential Technical Features The following figures are referred to which cover: Figure 1: Side and end views of a rotor (1 ) consisting of one blade system for a cross flow fuid turbine. One blade system consists of one inclined blade (3) and two or more arms (7 and 9) each supporting a balance weight (4 and 5) and all attached to a hub (6) which is then attached to the main rotation shaft.

Figure 2: Side and end views of a fluid flow turbine rotor (1) (consisting of one blade system (2)) supported by a stationary support structure (8). The rotor rotates around the y-axis attached to a pwer shaft (centred and aligned with the y-axis) and normal teetering variants teeter about the z-axis. The example shown is a single bladed vertical axis wind turbine supported by a short tower.

Figure 3: Side and end views of a fluid flow turbine rotor (I) consisting of one blade system(2) supported by a stationary support structure (8). The dotted outlines show the position of the blade and balance weight when the blade is in its parking position (aliigned with the x-axis). The example shown is a single bladed vertical axis wind turbine supported by a short tower.

According to the present invention all of the elements rotating about the y-axis are referred to as the rotor (1) and the rotor is made up of one or more blade systems (2).

These blade systems are composed of three main components the blade (3) and two or more balance weights (A and C) (4 and 5) arranged as shown in Figures 1 to 3 and all attached to a hub (6).

The blade (3) consists of a relatively long and slender planar element similar to the wing of an aeroplane. The cross sectional shape of the blade is usually of an aerofoil section but can take other forms such as a static or rotating cylinder (rotating about the major axis (L) of the blade). The blade is usually straight, but can be bent and/or curved and/or twisted and may be fixed or variable pitched.

The blade is attached to the hub at an angle () to the v-axis measured about the w and z-axes. The arm (7) supporting balance weight (A) (4) is rigidly attacned to the hub at the same angle () in relation to the v-axis but mirrored about the u-axis. The preferred angle for () is 45 degrees. If, when the turbine is not operating, the blade is to be parked in-line with the x-axis (or alternatively in line with the y-axis) then two arms (7a and 7b) each supporting balance weights (Al and A2) (4a and 4b) will be required as shown in Figure 3 to enable clearance of the stationary support structure or tower (8).

The arm (9) supporting balance weight C (10) is attached to the hub (6) at an angle of 90 degrees to the v-axis and opposite to the blade (3) in relation to the v-axis.

This arm can also be designed to pivot or rotate about the z-axis (relative to the rest of the blade system) so that the blade can be parked in line with the x-axis (or alternatively in line with the y-axis).

The whole rotor assembly (1) rotates about the y-axis via a hub (6) attached to a power shaft centrally aligned with the y-axis and supported by one or more bearings attached to a stationary support structure or tower (8).

The hub can be attached rigidly to the shaft by mechanical or adhesive means.

Alternatively the hub of the blade system may be attached to the rotor's power shaft via a teeter shaft supported by bearings which is normally aligned with both the z and w-axes. This permits the whole blade system to rotate "to and fro" independently through an teeter angle of ep about the z and w-axes as the rotor (1) rotates about the y-axis. This "to and fro" rotation or "see-saw" action is known as "teeter" and the axis about which it rotates is known as the teeter axis.

The invention has a number of additional variants: a. Teetered rotor with rotated teeter axis: The blade system can also be designed to teeter about an axis (d-axis) which is not in line with the z or w-axis, but is itself rotated about the v-axis by an angle 6 and/or additionally rotated about the u-axis by an angle ss.

b. Teetered rotor with offset teeter axis A further variant is to offset the teeter axis (w-axis or d-axis) along the x-axis in either direction so that the whole rotor teeters about this axis or only the blade and balance weight A part of the blade system can rigidly do so.

c. Two bladed rotor with independent blade systems This variant is like the previously described variants except that the rotor is composed of two independent blade systems teetering on either on a common teeter axis or two separate teeter axes.

d. Two bladed teetered rotor A further variant applies to a two bladed teetered rotor in which balance weights can be omitted for each blade and the whole rotor is designed to teeter or see-saw as one rigid unit.

e. Multi bladed with flapping blade systems.

In this variant the blade systems consist of the blade and balance weight A but with balance weight C omitted. In essence it is similar to variant b. described above except that the hub supports offset (along x-axis) teetering (or flapping) pivots for more than one blade.

Claims

1. A cross-flow fluid turbine for extracting power from a moving fluid, consisting of a rotor consisting of one or more blade systems each consisting of an inclined (relative to the rotor's rotation axis y) slender planar aerodynamic blade combined with two or more arms supporting balance weights, each attached to a hub on the rotor's rotation axis and arranged as per Figures 1 and

2 2. A cross-flow fluid turbine as described in claim one such that the rotor is neutrally stable when stationary and positively stable when rotating.

3. A cross-flow fluid turbine as described in claim one and claim two such that the centre of gravity of the spinning rotor lies at the hub.

4. A cross-flow fluid turbine as described in claim one and claim two such that the centre of gravity of the spinning rotor lies at or near the hub.

5. A cross-flow fluid turbine as described in claim one and two, in which the rotor is able to teeter in a see-saw action about a teeter axis aligned with z and w-axes as the rotor rotates about the y-axis (turbine's rotation axis) as described in Figure 2.

6. A cross-flow fluid turbine as described in claim one and two, in which the rotor is able to teeter in a see-saw action about a teeter axis (d-axis) at the hub in a manner similar to that in claim six, except that the d-axis is at an angle 6 about the v-axis, relative to the w-axis.

7. A cross-flow fluid turbine as described in claim one and two, in which the rotor is able to teeter in a see-saw action about a teeter axis (d-axis) at the hub in a manner similar to that in claim six except that the d-axis is at an angle ss about the u-axis, relative to the w-axis.

8. A cross-flow fluid turbine as described in claim one and two, in which the rotor is able to teeter in a see-saw action about a teeter axis (d-axis) at the hub in a manner similar to that in claim six, except that the w-axis is offset along the x axis 8 about the v-axis, relative to the w-axis.

9 A cross flow fluid turbine with two or more blades similar to that described in claim one except that balance weight C for each blade system is omitted.

10 A cross flow fluid turbine similar to that in claim 9 except that each blade system (consisting of blade and balance weight A) are able to teeter or flap about an independent teeter axis (w or d-axis) offset along the u-axis at the hub.

11 A two bladed cross-flow fluid turbine similar to that in claim 9 in which the whole rotor teeters about the same teeter axis (w or d-axis) as a single rigid body.

Key to Figures 1, 2 and 3 1: Rotor.

2: Blade-balance weight system.

3: Blade.

4: Balance weight A.

4a: Balance weight A part a.

4b: Balance weight A part b.

5: Balance weight C.

6: Rotor hub.

7: Support arm for Balance weight A.

7a: Support arm for Balance weight A part a.

7b: Support arm for Balance weight A part b.

8: Stationary support structure or stub tower.

9: Support arm for Balance weight C.

10: Blade (3) in normal operating position.

11: Blade (3) in 'parked' position.

12: Support arm for Balance weight C in 'parked' position.

13: Balance weight A in 'parked' position.

14: Balance weight C in 'parked' position.

A: Balance weight A.

C: Balance weight C.

L - Axis: Major (long or 'span-wise) axis of blade (3).

u - Axis: Axis to which support arm (9) for balance weight C is aligned. Normally the u - Axis is set at 90 degrees to v - Axis.

v - Axis: Axis about which the blade tilt angle 9 is measured.

w - Axis: Axis about which the rotor (1) and blade system (2) rotates or 'teeters' in a 'see-saw' action. Normally the w - Axis is at 90 degrees to the L - Axis and to the u - Axis, but (as the d - Axis) can be at other angles (8) to the L - Axis and u - Axis. Additionally as the d - Axis can be rotated by an angle ss about the u - Axis.

Additionalty the w - Axis can be offset along the x - axis.

x - Axis: Axis to which the blade (3) is aligned when the blade is parked.

y - Axis: Axis about which the rotor (1) and blade system (2) rotates when operating to drive the power shaft.

z - Axis: Axis about which the rotor (1) and blade system (2) rotates or 'teeters' in a 'see-saw' action. Normally the z - Axis is at 90 degrees to the L - Axis and to the u - Axis, but (as the d - Axis) can be at other angles (8) to the L - Axis and u - Axis. Additionally as the d - Axis can be rotated by an angle ss about the u - Axis.

Tilt angle of blade (3) and balance weight A support arm (7) (about w - Axis) measured from v - Axis.

zp Teeter angle about w - Axis.

8 Rotated teeter axis angle about v - Axis.

ss Rotated teeter axis angle about u - Axis.