GB2373028A

GB2373028A - Turbines

Info

Publication number: GB2373028A
Application number: GB0209160A
Authority: GB
Inventors: Alan John Rogan
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-03-21
Filing date: 2001-03-21
Publication date: 2002-09-11
Anticipated expiration: 2021-03-21
Also published as: GB2373028B; GB0209160D0

Abstract

A wind-powered turbine has two rotors 30,31 mounted at opposite ends of a horizontal boom 32, each with vanes 36-39 pivoted at points 44 to radial arms 41. Rods 45 connecting the vanes 36-39 to a common pivot 47 on a crank-arm 48, vary the pitch orientation of each vane cyclically from radial to tangential relative to its rotor and then back to radial during successive half revolutions of the rotor. The arm 48 is adjusted angularly to vary the phasing of the pitch-cycle for speed control of the rotors, and the boom 32 is turned on a vertical shaft 52 across the wind-direction sensed by a vane 62 or, for safety in high-wind conditions sensed by an anemometer 63, into alignment with the wind. The turbine may alternatively be used for harnessing flow in water or other fluids.

Description

Turbines

This invention relates to turbines.

The invention is particularly concerned with turbines of the kind in which a rotor is used having vanes that are individually pivoted to the rotor and are each turned to vary its pitch as the rotor rotates. Turbines of this kind are known for use in harnessing wind power and in this context are commonly referred to as'windmills', but are applicable also for harnessing flow in water or other fluids.

According to the present invention there is provided a turbine wherein two rotors are mounted spaced apart from one another on a carrier with their rotational axes colinear, the carrier is mounted for angular displacement about an axis that is located between the two rotors at right angles to their rotational axes, and wherein each rotor has vanes that are individually pivoted to the rotor and includes a plurality of links that are coupled to the vanes respectively for turning them on their respective pivotal axes such that the pitch orientation of each vane varies cyclically from radial to tangential relative to the rotor and then back to radial during successive half revolutions of the rotor, each link of the rotor intercoupling its respective vane with a point which is common to all those links, and the common point being a point offset from the rotational axis of the rotor and relative to which the rotor rotates.

The rotational axis of each rotor may be substantially horizontal, and the axis for angular displacement of the carrier may then be substantially vertical to enable variation of orientation of the rotors in azimuth. In

these latter circumstances, provision may be made for adjusting the angular displacement of the carrier about its substantially-vertical axis in dependence upon the direction of flow of the wind or other driving fluid so as to maximise, or otherwise, the speed of rotation of the rotors. A measure of protection of the turbine against damage in circumstances in which the speed of the wind or other driving fluid becomes excessive, may be achieved by turning the carrier so as to bring the rotational axes of the rotors substantially into alignment with the flow-direction.

A windmill in accordance with the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an illustrative side elevation of the windmill according to the invention; Figure 2 is a schematic representation to reduced scale, of one of two rotors of the windmill, as viewed on the line II-II of Figure 1; and Figure 3 is illustrative to enlarged scale, of detail of the windmill viewed in the direction of the arrow III of Figure 1.

Referring to Figures 1 and 2, the windmill has two rotors 30 and 31 which are located at opposite ends of a horizontal boom 32 that is rotatable on a bearing 33 at the top of a tower 34 of a cabin 35. Each rotor 30 and 31 comprises four vanes 36 to 39 that are carried on a hollow shaft 40 by respective mutually-orthogonal arms 41 of equal length, for rotation in a vertical plane about the horizontal axis 42 of the shaft 40.

The vanes 36 to 39 of each rotor 30 and 31 have mountingbrackets 43 that are attached to the rotor-arms 41 by pivots 44. Regulation of the pitch of each vane 36 to 39 about its pivot 44 is effected in each case by an individual control rod 45 that at its outer end is attached to the bracket 43 of that respective vane through a pivot 46. The inner ends of the control rods 45 are attached individually through a common pivot 47 to the outer end of a crank-arm 48 of a shaft 49 which extends coaxially within the shaft 40.

The co-linear shafts 40 of the rotors 30 and 31 are coupled via respective bevel gears 50 to a bevel gear 51 of a vertical hollow shaft 52 within the tower 34, whereas (as illustrated more clearly in Figure 3) the shafts 49 are coupled via respective bevel gears 53 to a

bevel gear 54 of a shaft 55. The shaft 52 is coupled at I its lower end within the cabin 35 to the rotor of an electrical generator 56, and the shaft 55 extends through this from a gearbox 57 that is driven by a stepping-motor or servo unit 58.

For each rotor 30 and 31, the coupling of the control rods 45 to the pivot 47 offset from the rotor-axis 42, is effective to cause the pitch of each vane 36 to 39 to vary cyclically throughout each revolution of the rotor, as the pivots 44 and 46 follow overlapping circular paths centred on the axis 42 and the pivot 47 respectively (Figure 2). More particularly, the pitch of each vane relative to its arm 41 varies progressively, but not at a uniform rate, through each revolution of the rotor.

During each revolution, each vane 36 to 39 follows a cyclic pattern of progressively-changing pitch which, if considered as starting from the condition (represented in Figure 2 by the vane 36) in which it is radial relative to the rotor (facing at right angles to its arm 41), it turns 135 degrees relative to its arm 41 in each of the

first and second quadrants, and 45 degrees in each of the third and fourth quadrants ; the vane accordingly takes up the orientations corresponding to those of the vanes 37, 38,39 and 36 in Figure 2 at the ends of the first, second, third and fourth quadrants respectively. This cyclic pattern of progressively-changing pitch in which the vane turns from radial to tangential relative to the rotor and then back to radial through successive half revolutions, is followed by each vane 36 to 39.

Manual or automatic control of the unit 58 is effective to vary via the gearbox 57 and the shaft 55, and thence via the shafts 49, the corresponding angular settings of the crank-arms 48 of the rotors 30 and 31. This setting determines the location or angular phasing in the vertical plane of the nominal start of the cyclic pattern of vane-pitch variation of each rotor 30 and 31. The optimum phasing (for maximum torque) is that in which the vanes 36 to 39 of the rotor are radial so as to face horizontally, either at the bottom or the top of the revolution; the rotors 30 and 31 are illustrated with this phasing in Figures 1 and 2, the horizontally-facing vane condition being at the bottom for the rotor 30 and at the top for the rotor 31 to afford balance. If with this setting of the crank-arms 48, the boom 32 is turned across the wind (the condition illustrated in Figure 2), maximum torque will be exerted by both rotors 30 and 31 to obtain maximum speed of rotation of the shaft 52 and output from the generator 56. The speed can be reduced, simply by adjusting the angular settings of the crankarms 48 through the unit 58.

The boom 32 is maintained turned across the wind by means of an electric motor 59 that drives it in azimuth on the bearing 33, via gearing 60. The motor 59 is in this respect controlled from a unit 61 that responds to the orientation of a wind-deflected vane 62 mounted

externally of the cabin 35. The unit 61 is also responsive to dangerous high-wind conditions indicated by an anemometer 63, to activate the motor 59 to turn the boom 32 into alignment with the wind so that the vanes 36 to 39 are then all edge-on to the wind direction for safety.

Although in the example of windmill described above, each of the rotors has four vanes, they may have fewer or more. Furthermore, solar panels (such as indicated in chain-dotted outline SP on the panels 36 in Figure 1) may be attached to the vanes so that electrical power is available irrespective of whether the wind is blowing.

The principle of the pitch-angle adjusting mechanism used in the windmills described above may be applied to the comparable adjustment of vanes of a water-current driven turbine. More especially, the rotors of the windmill described above may be utilised underwater to derive power from water current.

Claims

Claims : 1. A turbine wherein two rotors are mounted spaced apart from one another on a carrier with their rotational axes co-linear, the carrier is mounted for angular displacement about an axis that is located between the two rotors at right angles to their rotational axes, and wherein each rotor has vanes that are individually pivoted to the rotor and includes a plurality of links that are coupled to the vanes respectively for turning them on their respective pivotal axes such that the pitch orientation of each vane varies cyclically from radial to tangential relative to the rotor and then back to radial during successive half revolutions of the rotor, each link of the rotor intercoupling its respective vane with a point which is common to all those links, and the common point being a point offset from the rotational axis of the rotor and relative to which the rotor rotates.
2. A turbine according to Claim 1 wherein the rotational axis of each rotor is substantially horizontal.
3. A turbine according to Claim 2 wherein the axis for angular displacement of the carrier is substantially vertical to enable variation of orientation of the rotors in azimuth.
4. A turbine according to Claim 3 including means for sensing the flow-direction in azimuth of driving fluid incident on the vanes of the rotors, and means for adjusting the angular displacement of the carrier about its substantially-vertical axis in dependence upon the sensed flow-direction.
5. A turbine according to Claim 4 including means for sensing the flow-rate of the driving fluid incident on the vanes of the rotors, and wherein the means for adjusting the angular displacement of the carrier is operative in dependence upon the flow-rate sensed to turn the carrier about its substantially-vertical axis to bring the rotational axes of the rotors substantially into alignment with the sensed flow direction.
6. A turbine according to any one of Claims 1 to 5 wherein the carrier is an elongate boom and the two rotors are mounted at opposite ends of the boom.
7. A turbine according to any one of Claims 1 to 6 wherein the vanes of each rotor are pivotally mounted on respective radial arms of the rotor.
8. A turbine according to any one of Claims 1 to 7 wherein the links comprise individual rods.
9. A turbine according to any one of Claims 1 to 8 wherein said common point of each rotor is a point on a member individual to that rotor, said member being angularly displaceable about the rotational axis of its rotor for varying the angular phasing about that axis of the cyclic pitch variation of the vanes of that rotor.
10. A turbine according to Claim 9 wherein each rotor is carried by an individual rotatably-mounted shaft and a shaft coaxial with this shaft carries the said member individual to that rotor.
11. A turbine according to Claim 9 or Claim 10 including means for adjusting the angular displacement of said member about the rotational axis of its rotor for regulating the speed of rotation of that rotor.
12. A turbine according to any one of Claims 1 to 11 operable as a windmill.
13. A windmill substantially as hereinbefore described with reference to Figures 1 to 3 of the accompanying drawings.