A water turbine is disclosed comprising a rotor mounted to be rotatable about an axis. The rotor comprises at least three blades for causing the rotor to rotate about the axis when the blades are located in flowing water. The rotor comprises a plurality of members in the form of a triangulated structure, and at least one of said members comprises one of said blades.
1. A transverse flow water turbine comprising a rotor mounted to be rotatable about a substantially horizontal axis, the rotor comprising at least two planes perpendicular to the axis and at least three blades disposed between the at least two planes, each of the at least three blades supported at a first and second end by one of the at least two planes, and the at least three blades causing the rotor to rotate about the axis when the blades are located in flowing water,
wherein the rotor comprises a plurality of members in the form of a structure triangulated in three dimensions, wherein at least one of said blades comprises one of said members, wherein said at least one blade is elongate and has a line that is substantially straight, wherein the line of said at least one blade is not parallel to said axis and is arranged such that the line of the blade and the axis do not lie in a common plane, wherein the plurality of members form a plurality of triangles, and wherein at least one of the plurality of triangles of the structure triangulated in three dimensions comprises one of the at least two planes and two of the at least three blades.
2. A transverse flow water turbine according to claim 1 , comprising at least six blades forming members of the triangulated structure.
3. A transverse flow water turbine according to claim 1 , wherein each blade is substantially straight.
4. A transverse flow water turbine according to claim 1 , wherein at least one blade has an aerofoil profile.
5. A transverse flow water turbine according to claim 1 , wherein at least one blade is an aerofoil twisted along its length.
6. A transverse flow water turbine according to claim 1 , wherein, at least one location along said axis, a plane perpendicular to said axis is intercepted by at least six members of said triangulated structure.
7. A transverse flow water turbine comprising:
a rotor mounted to be rotatable about an axis;
at least three blades mounted to the rotor for causing the rotor to rotate about the axis when the blades are located in flowing water, wherein at least one blade is an aerofoil twisted along its length; and
a plurality of members included in the rotor and being in the form of a structure triangulated in three dimensions,
wherein at least one blade comprises one of the members, wherein the at least one blade is elongate and includes a line that is substantially straight, and wherein the line of the blade is not parallel to the axis and is arranged such that the line of the blade and the axis do not lie in a common plane.
8. A transverse flow water turbine according to claim 7 , comprising at least six blades forming members of the triangulated structure.
9. A transverse flow water turbine according to claim 7 , wherein each blade is substantially straight.
10. A transverse flow water turbine according to claim 7 , wherein at least one blade has an aerofoil profile.
11. A transverse flow water turbine according to claim 7 , wherein said axis is substantially horizontal.
12. A transverse flow water turbine according to claim 7 , wherein, at least one location along said axis, a plane perpendicular to said axis is intercepted by at least six members of said triangulated structure.
13. A transverse flow water turbine according to claim 12 , wherein the plurality of members form a plurality of triangles, and wherein at least one of the plurality of triangles of the structure triangulated in three dimensions comprises one of the at least two planes and two of the at least three blades.
14. A transverse flow water turbine according to claim 7 , wherein the rotor includes at least two planes perpendicular to the axis and the at least three blades disposed between the at least two planes, each of the at least three blades supported at a first and second end by one of the at least two planes.
15. A transverse flow water turbine comprising a rotor mounted to be rotatable about a substantially horizontal axis, the rotor comprising at least two planes perpendicular to the axis and at least three blades disposed between the at least two planes, the at least three blades causing the rotor to rotate about the axis when the rotor is located beneath the surface of flowing water,
wherein the rotor comprises a plurality of members in the form of a structure triangulated in three dimensions, wherein at least one of said blades comprises one of said members, wherein said at least one blade is elongate and has a line that is substantially straight, wherein the line of said at least one blade is not parallel to said axis, wherein the plurality of members form a plurality of triangles, and wherein at least one of the plurality of triangles comprises one of the at least two planes and two of the at least three blades.
16. A transverse flow water turbine according to claim 15 , wherein each of the at least three blades is supported at a first end and a second end by one of the at least two planes.
17. A transverse flow water turbine according to claim 16 , wherein, the first end of a first of the at least three blades is engaged with the first end of a second of the at least three blades on one of the at least two planes, and the second end of the second of the at least three blades is engaged with the second end of a third of the at least three blades on the other of the at least two planes.
18. A transverse flow water turbine according to claim 15 , wherein the line of said at least one blade and the axis do not lie in a common plane.
19. A transverse flow water turbine according to claim 15 , wherein the blades are located beneath the surface of flowing water.
20. A transverse flow water turbine according to claim 15 , wherein at least one blade is an aerofoil twisted along its length.