초록 ▼

A fan assembly includes a vertical axis wind turbine (VAWT) which is coupled to an air extraction or air supply fan. The VAWT is located above and is coupled coaxially to the fan. The fan assembly also includes an auxiliary turbine to provide start-up torque to initiate rotation of the VAWT. The VAW

A fan assembly includes a vertical axis wind turbine (VAWT) which is coupled to an air extraction or air supply fan. The VAWT is located above and is coupled coaxially to the fan. The fan assembly also includes an auxiliary turbine to provide start-up torque to initiate rotation of the VAWT. The VAWT is typically a Darrieus-type turbine and the auxiliary turbine is typically a Savonius-type turbine. In the preferred embodiments, the fan assembly includes a rotational speed governor to avoid damage to the turbine and/or fan in high winds.

대표청구항 ▼

1. A fan assembly comprising a vertical axis wind turbine including a multi-blade Darrieus or Gyromill-type rotor coupled to a separate, upright axis air extraction or air supply fan to drive the fan.2. A fan assembly according to claim 1 wherein the vertical axis wind turbine is coupled coaxially t

1. A fan assembly comprising a vertical axis wind turbine including a multi-blade Darrieus or Gyromill-type rotor coupled to a separate, upright axis air extraction or air supply fan to drive the fan.2. A fan assembly according to claim 1 wherein the vertical axis wind turbine is coupled coaxially to the fan.3. A fan assembly according to claim 2 wherein the vertical axis wind turbine is coupled to the fan via intermediate gearing which increases the rotary speed of the fan relative to that of the turbine.4. A fan assembly according to claim 1 wherein the vertical axis wind turbine includes angularly spaced, vertically oriented aerofoil-profile turbine blades which are symmetrical or cambered in cross-section.5. A fan assembly according to claim 1 and comprising rotational speed governing means to limit the rotational speed of the turbine.6. A fan assembly according to claim 5 wherein the speed governing means comprises a braking member carried by a rotating component of the fan assembly and arranged to be moved, by centrifugal forces, against a stationary part of the fan assembly when the rotary speed of that component exceeds a predetermined value.7. A fan assembly according to claim 6 wherein the fan includes an impeller relative to which the braking member is connected pivotally.8. A fan assembly according to claim 5 wherein the turbine blades are connected pivotally to radial spokes at upright pivot axes about which the blades can pivot relative to the spokes.9. A fan assembly according to claim 8 wherein the spokes comprise elongate rods encased in aerodynamically shaped casings.10. A fan assembly according to claim 8 wherein the pivot axes are off-set from the centers of gravity of the associated turbine blades, the off-set being such that when the turbine rotates centrifugal forces tend to urge the blades to assume a negative pitch.11. A fan assembly according to claim 10 and comprising springs biasing the turbine blades towards orientations of efficient pitch, the springs being selected for their bias to be overcome when the rotary speed of the turbine exceeds a predetermined value, whereby when the predetermined rotary speed of the turbine is exceeded the springs allow the blades to assume a negative pitch, thereby decreasing the efficiency of the turbine.12. A fan assembly according to claim 1 and comprising an auxiliary turbine coupled to the vertical axis wind turbine to provide start-up torque to initiate rotation of the vertical axis wind turbine.13. A fan assembly according to claim 12 wherein the auxiliary turbine has a vertical axis of rotation and is coupled coaxially to the vertical axis wind turbine and to the fan.14. A fan assembly according to claim 13 wherein the vertical axis wind turbine comprises angularly spaced, vertically oriented turbine blades which are spaced radially from the axis of rotation of the turbine, and the auxiliary turbine is located on that axis.15. A fan assembly according to claim 14 wherein the auxiliary turbine is a Savonius-type turbine.16. A fan assembly according to claim 15 wherein the turbine is of stepped helical construction.17. A fan assembly according to claim 15 wherein the auxiliary turbine is of continuous helical construction.18. A fan assembly according to claim 1 wherein the fan comprises an axial inlet, radio exhaust fan impeller which includes a plurality of blades that are backwardly swept relative to the direction of rotation of the impeller.19. A fan assembly according to claim 18 comprising a windshield located about the radial exhaust of the fan.20. A fan assembly according to claim 18 wherein the inlet of the fan impeller is coupled to a vertical duct extending from a space from which air is to be extracted.21. A fan assembly according to claim 20 wherein the duct is downwardly tapered.22. A fan assembly according to claim 20 comprising a support ring supported off the duct and surrounding it, the support ring supporting the windshield.23. A fan assembly according to claim 22 wherein the ring carries foot support platforms on which personnel can stand.24. A fan assembly according to claim 20 wherein the impeller is mounted on a central shaft which is supported on bearings in the duct and which extends to a position beneath the duct to provide a rotary power take-off.25. A fan assembly according to claim 1 comprising a manually operable brake, acting between the duct and the fan impeller, to brake the fan impeller.