Wind turbine

Abstract

A wind-powered turbine has vanes ( 2 - 5;36 - 39 ) that are pivoted ( 13;44 ) to radial arms ( 6;41 ) of its rotor ( 1;30,31 ) and are turned by rods ( 14;45 ) linking the vanes ( 2 - 5;36 - 39 ) individually to a common pivot ( 16;47 ) which is offset from the rotor-axis ( 8;42 ) on a crank-arm ( 17;48 ). The rods ( 14;45 ) constrain their pivots ( 15;46 ) with the vanes ( 2 - 5;36 - 39 ), to follow a circular path (B) centred on their common pivot ( 16;47 ) on the crank-arm ( 17;48 ) so that vane-pitch varies cyclically with rotor-rotation. Angular adjustment of the crank-arm ( 17;48 ) about the rotor-axis ( 8;42 ) varies the angular phasing of the pitch cycle within each revolution such that for constant wind speed and direction (W), rotor-speed changes. Where the rotor-axis ( 8 ) is vertical, maximum output torque is maintained by turning the crank-arm ( 17 ) in response to change of wind-direction sensed by a sensor-vane ( 21 ), and the rods ( 14 ) include hydraulic rams ( 23 ) for varying rod-lengths in feathering the vanes ( 2 - 5 ) into edge-on alignment with the wind when an anemometer ( 26 ) senses high-wind conditions. Where the rotor-axis ( 42 ) is horizontal, two rotors ( 30,31 ) are mounted at opposite ends of a boom ( 32 ) that is turned across the wind according to wind-direction sensed by a vane ( 62 ), and in high-wind conditions sensed by an anemometer ( 63 ) is turned into alignment with the wind.

1 . A turbine having a rotor with vanes that are individually pivoted to the rotor, wherein means for turning each vane on its pivotal axis to vary the pitch of the vane cyclically with rotation of the rotor, is coupled to a coupling point on the vane spaced from that axis and is operative during rotation of the rotor to constrain the coupling point to follow a circular path having its centre offset from the rotational axis of the rotor.  
     
     
         2 . A turbine according to  claim 1  wherein the vanes are pivotally mounted on respective radial arms of the rotor.  
     
     
         3 . A turbine according to  claim 1  or  claim 2  wherein said means comprises a plurality of links which respectively intercouple the coupling points of the vanes with a common point that is offset from the rotational axis of the rotor and relative to which the rotor rotates.  
     
     
         4 . A turbine according to  claim 3  wherein the links comprise individual rods.  
     
     
         5 . A turbine according to  claim 3  or  claim 4  wherein said common point is a point on a member that is angularly displaceable about the rotational axis of the rotor for varying the angular phasing about that axis of the cyclic pitch variation of each vane.  
     
     
         6 . A turbine according to  claim 5  wherein the rotor is carried by a rotatably-mounted shaft and said member is carried by a shaft that is coaxial with the rotor shaft.  
     
     
         7 . A turbine according to  claim 5  or  claim 6  including means for sensing the flow-direction relative to the rotational axis of the rotor of driving fluid incident on the vanes, and means for adjusting the angular displacement of said member about the rotational axis of the rotor in dependence upon the sensed flow-direction.  
     
     
         8 . A turbine according to any one of  claims 3  to  7  wherein the links include means for selectively varying their relative lengths from the condition in which they are all of substantially the same length as one another, for feathering the vanes.  
     
     
         9 . A turbine according to  claim 8  including means for sensing the flow-rate of driving fluid incident on the vanes, and means for varying the relative lengths of the links as aforesaid in dependence upon the sensed flow-rate.  
     
     
         10 . A turbine according to any one  claims 1  to  9  wherein the rotational axis of the rotor is substantially vertical.  
     
     
         11 . A turbine according to any one  claims 1  to  6  wherein the rotational axis of the rotor is substantially horizontal.  
     
     
         12 . A turbine according to any one of  claims 1  to  6  comprising a plurality of said rotors mounted for rotation in substantially parallel planes.  
     
     
         13 . A turbine according to  claim 12  wherein the planes of rotation of the rotors are substantially vertical.  
     
     
         14 . A turbine according to  claim 13  comprising two said rotors mounted at opposite ends of a boom with their axes of rotor-rotation co-linear.  
     
     
         15 . A turbine according to  claim 14  wherein the boom is mounted for angular displacement about a substantially vertical axis for varying the orientation of the rotors in azimuth.  
     
     
         16 . A turbine according to  claim 15  including means for sensing the flow-direction in azimuth of driving fluid incident on the vanes, and means for adjusting the angular displacement of the boom about the substantially vertical axis in dependence upon the sensed flow-direction.  
     
     
         17 . A turbine according to  claim 16  including means for sensing the flow-rate of the driving fluid incident on the vanes, and wherein said means for adjusting the angular displacement of the boom is operative to turn the rotational axes of the rotors into substantial alignment with the sensed flow-direction in dependence upon the sensed flow-rate.  
     
     
         18 . A turbine according to any one of  claims 1  to  17  operable as a windmill.