CA2225425A1 - Walter's whirl-wind vertical wind and water turbine (iii) - Google Patents

Abstract

A vertical axis wind turbine is supported by a frame held in place by an encircling series of crescent-shaped tubular deflector vanes. The vanes widen towards the turbine core, concentrating the wind. The energy of the wind is extracted by curved rotor impeller surfaces that spiral inwardly. Air following this inward path is directed to another adjacent spiral impeller surface to extract further energy. Air can be supplied to such cavities from a compressed air source driven by wave action on a body of water.

Description

CA 0222~42~ 1997-12-22 Title: WALTBR'~ WHIRL-WIND VBRTICAL AXIS WIND AND WATBR
TURBIN~ III

Field of the Invention This invention relates to wind and turbines of the type wherein a vertical shaft is turned by the wind or water. More particularly, it relates to an improved construction for the rotor of such a turbine.

Background to the Invention Vertical axis wind turbines have an ancient history going back to Persian windmills of the first millennium. By the end of the nineteenth century and early 20th century numerous designs were conceived for vertical axis windmills that incorporate a series of exterior vanes to deflect the wind entering the turbine and enhance its performance.
The present inventor has already obtained U.S.
Patent No. 5,664,418 for a wind turbine having a series of exterior wind-deflecting vanes that function as "columns" to support the wind turbine. Other prior art references show "funnelling" features leading up to the turbine inlets to concentrate and speed-up the wind as it enters the turbine impellers. The exterior vanes intrinsically serve to concentrate the wind as they extend between outer and inner cylindrical openings and close together in a normal, radial-like manner.

CA 0222~42~ 1997-12-22 Generally, the vertical series of known wind-receiving impellers and the outer encircling array of deflector vanes are held in place by respective pairs of end plates to which the ends of these components are fastened. The axis of the turbine itself is generally fitted into the upper plate which caps the deflector vanes and frames the turbine. As the force of the wind will develop a substantial toppling torque on the entire turbine structure, it is important that this outer frame formed by the deflector vanes and their end plates will constitute a ridged and stable structure.
This is all the more so true because the preferred aspect ratio for a vertical wind turbine will provide for a height that is greater than its width (providing for more wind-receiving surfaces in an elevated position). Thus, the stabilization of the outer deflector frame is akin to the problem of supporting a relatively small roof with an encircling series of relatively lengthy columns and providing strength to resist lateral wind forces.
The present invention provides an improvement in the rotor portion of a wind turbine supported by outer, deflecting vanes. This invention improves the performance of such turbines by increasing the amount of energy taken from the air entering the turbine by making the air transfer from one inwardly curving spiral vane to CA 0222~42~ 1997-12-22 a second spiralled vane when exiting the first spiral vane. This contributes to the enhanced performance of the turbine.
By a further feature, a wind turbine according to the invention is suited for operation in conjunction with a source of compressed air as an alternative or supplemental power source to wind energy.
By a further feature, a turbine according to the invention is suited for use in extracting energy from water which is in motion. In particular, it is suited to being driven by a reciprocating or reversing flow of water.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification.

Summary of the Invention According to the invention in its broader aspect, a vertical axis turbine having a turbine rotor with vertical impeller surfaces is provided with a CA 0222~42~ 1997-12-22 surrounding circumferential series of vertically deployed deflector vanes, each of which is tubular (in the most general geometric sense) in shape, extending from an edge at its outer circumferential boundary and widening towards the central axis of the turbine to form a generally three-sided cross-section. This cross-section terminates with a base located at the inner circumferential boundary of the series of deflector vanes, sealingly positioned next to the outer circumferential path boundary of the turbine rotor. This three-sided cross-section is preferentially curved in a semi-crescent form to both concentrate the flow of a fluid, such as air or water, entering the turbine (beyond the concentration arising from the radial closing of the deflector vane's active surface) and deflect the fluid flow to direct it against the active surfaces of the turbine impellers at a more nearly perpendicular orientation.
As a special feature of the invention the rotor is provided with impeller vanes that spiral inwardly over half of the diameter of the rotor. Air received by the turbine impellers is forced to spiral inwardly by these vanes, and then is transferred to a second set of spirally shaped impeller surfaces whereby the remaining air pressure is utilized to turn the rotor. There is no CA 0222~42~ 1997-12-22 escapement of air occurring as only dead air remains on the down wind side of the rotor.
As an optional feature of the invention, the impeller surfaces of the turbine rotor itself may be formed by a series of thin tubular elements contained between upper and lower turbine end plates, such tubular elements also having a triangular-like or semi-crescent shaped cross-section that is not necessarily the same as that of the deflectors.
By a further feature of the invention the rotor may be subdivided vertically and stacked to provide rotor segments that are shifted circumferentially with respect to each other. This reduces the tendency for vibration to develop in the turbine.
A model built which is 10 feet high to 10 feet wide has shown the extraction of power from the wind as there is effectively no wind exiting the lee side of the turbine.
By a further feature of the invention, this turbine may be modified to receive air from a source of pressurized air whereby the energy content of the pressurized air can drive the turbine. A convenient source of pressurized air can be provided by a wave-activated air compressor. Thus the turbine of the invention can be driven simultaneously by both wind and wave energy.

CA 0222~42~ 1997-12-22 In another variant of the invention the turbine may be immersed in a current of water and thereby extract energy from such current. Because of the capacity of the turbine to receive a fluid flow from essentially any direction the water current may be reciprocating, as occurs with wave action, or in a tidal race (i.e. a narrow passage through which tidal waters ebb and flow).
The foregoing summarizes the principal features of the invention and some of its optional aspects. The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow.

Summary of the Fiqures Figure 1 is a cross-sectional plan view of a prior art turbine as patented in U.S. Patent 5,664,418.
Figure 2 is a profile view of the turbine of Figure 1.
Figure 3 is a cross-sectional plan view of the new modified, inventive turbine rotor.
Figure 4 is a pictorial depiction of a wave-driven air compressor delivering air to the turbine of Figure 3.
Figure 4A is a variant rotor configuration wherein the rotor is divided into stacked, vertical segments.

CA 0222~42~ 1997-12-22 Figure 5 is a cross-sectional depiction of the turbine of Figure 3 immersed in a water current.

Description of the Preferred Embodiment In Figure 1 an inner turbine rotor 1 has a vertical axle 2 in the form of a pipe fixed at its lower end to the centre of the turbine lower end plate 3. A
series of turbine impellers 4 are formed from tubular sheet metal walls 5 which may optionally close towards the axle 2 to provide a generally triangular cross-section. The impeller cavities 4a have an active surface 6 and are closed-off from the interior axial volume 7 of the turbine to form a sealed impeller cavity.
At the outer circumferential boundary 20 of the turbine 1 the outer edges 21 of the impeller walls 5 pass so close to the inside surface of the closed base panel 17 on the tubular cylinder 9 that when an impeller cavity 4a is closed-off by the inside surface of the base panels 17 the air within the cavity 4a is trapped and substantially retains any pressurized condition it may have.
By forming the impeller cylinder 5 as a closed tube, a series of box-beam-like elements of corresponding strength are created. These may be fastened to the lower and upper turbine end plates 3, 3a as by welding or CA 0222~42~ 1997-12-22 bolting. This permits the turbine rotor 1 to be readily assembled into a strong, ridged structure.
Without the use of the triangular shaped tubular impellers, the turbine would require an extremely heavy single blade to stand the force of high winds.
As shown in Figure 2, the turbine 1 is held in place by an external frame 8 formed of a series of tubular deflector cylinders 9 fastened between lower and upper deflector end plates 10, lOa. The axle 2 of the turbine 1 is centrally mounted so as to be contained within the deflector end plates 10, lOa by low friction bearings 11 that bear against a conical bearing surface end plate 20.
The deflector tubes 9 have a generally three-sided cross-section, with a shape similar to a semi-crescent. They serve as "pillars" for supporting the end plates 10, lOa. This, as with the impeller cylinders 5, forms a box-beam-like element that provides great structural integrity and stability for the frame 8, allowing the turbine 1 to be free-standing and self-supporting.
The main problem causing failure in the other types of windmills is the high wind factor. The wind turbine of the invention can be built to withstand very strong winds with the pillars 9 supporting the turbine in the face of high winds coming from all directions. It is CA 0222~42~ 1997-12-22 during the high wind period that the greatest amount of generating capacity is available.
The deflector tubes 9 provide a series of radial openings 12 that are tapered inwardly as proceeding to the deflector exit throat 13. This taper narrows the cross-sectional area for air entering the turbine rotor 1, forcing the air to increase its velocity. This feature is particularly important since the power available from the wind rises with the cube of wind velocity. Because of the widening that develops between the forward 14 and rearward 15 face of each deflector tube 9 as approaching the exit throat 13, a greater degree of narrowing of the air flow passageway in the exit throat 13 is established than would occur if the deflector tubes 9 were simply flat plates.
Concentration ratios ranging from 5:1 to 11:1 may be employed. These are not limits for the degree of narrowing that may be employed, but are exemplary values.
To remove rotary power from the turbine rotor 1, an automobile differential 16 type of arrangement is shown. The drive shaft 23 is coupled to the turbine shaft 2 and enters the differential gear box 18. The split axle drive shafts 19 carry power through brakes 20 and wheel-plate couplers 21 to electrical generators 22.
Through use of differential gearing and dual generators the speed of one generator can be held fixed while surges CA 0222~42~ 1997-12-22 in the speed of the turbine can be absorbed in the second generator 22. Alternately, one arm 22a of the differential 16 can be operated as a motor (while the generator 22 is locked by the brake 20) so as to keep the turbine in motion at all times. This will keep the turbine turning and allow it to respond rapidly to a rise in wind speed over the threshold operating value, for example, 10 miles per hour, when this threshold is I exceeded.
The new inventive form of rotor for this wind turbine is shown in Figure 3. In this design the wind 55 must flow both into the rotor along the spiral vane surfaces 50 and then along the further spiral surfaces 50A. The wind 55 is thereby effectively exhausted of its energy.
In Figure 4A two rotor segments 51,52 are shown stacked one on top of the other. The locations of the vanes 53,54 within each section 51,52 are shifted with respect to each other circumferentially. This spreads out the force of the wind on the vane surfaces 50 over time, reducing the "pulsing" effect of the wind and reducing vibrations.
While two rotor sections 51,52 are shown in Figure 4A, three or more may be employed for even smoother operation.

CA 0222~42~ 1997-12-22 In Figure 4, an anchored and stabilized ship's hull 39 is modified to support a rocking arm 30 that is hinged about a pivot 31. One end of this arm carries a flotation tank 32. The other end is coupled to a piston rod 33 that compresses air in a cylinder 34.
The compressed air is fed to one of the closed tubular cylinders 9a of the turbine 1 that is modified as shown in Figure 4 to have an air inlet 35 for receiving air into the inner volume portion 36. This modified cylinder 9a has an air outlet 37 that directs air against the active surface 6 of the impellers 4 as they pass by the modified base 20a of the cylinder 9a.
In operation, waves 38 raise and lower the tank 32, pumping air into the turbine 1 through the modified cylinder 9a and air outlet 37 to drive it and the generators 22. An advantage of this arrangement is that the turbine 1 can continue to generate power when the wind drops if waves 36 are present.
As depicted, the turbine, when mounted on a ship's hull 39 can be driven simultaneously by wind and wave 38 energy. Other sources of compressed air may, however, be provided. For example, compressed air stored in an underground salt dome can be built-up by air compressors that are driven by surplus electrical power.
The turbine 1 itself may be the source of such power.
The turbine of the invention in such cases is useful CA 0222~42~ 1997-12-22 because of the capacity of the turbine rotor l to receive wind directly from between the vanes 9; and also to receive air coming from a compressed air source that is directed through the interior of at least one of such sealed vanes 9a to impel rotation of the rotor l.
According to a further application of the invention as depicted in Figure 5, the turbine of the invention may be inverted and mounted with its rotor entirely or partially immersed in water. In such applications, the generators 22 are positioned above the rotor l.
In Figure 5, a barge 40 is anchored by cables 41 in shallow water above the sea bed 42. Preferably, the barge l is positioned in a tidal race or where reciprocating water flow 46 arises, as from wave action.
The turbine rotor l is immersed with the vanes 9 below the barge 40. The axle shaft 17 of the rotor l penetrates through the hull 43 of the barge 40, sealed by a water-tight seal 44. A bearing 45 supports the axle shaft 17. As previously depicted, generators 22 are coupled to the rotor l through a shaft coupling system which may include a differential 18.
Because of the deflecting action of the vanes 9, the turbine can receive water flow 46 from several directions. Thus, both when the tide flows in, and when it ebbs back to sea.

CA 0222~42~ 1997-12-22 Conclusion The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only exemplary. The invention in its broadest, and more specific aspects, is further described and defined in the claims which now follow.
These claims, and the language used therein, are to be understood in terms of the variants of the invention which have been described. They are not to be restricted to such variants, but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein.

CA 0222~42~ 1997-12-22 I CLAIM:

1. A vertical axis turbine having a turbine rotor with a vertical axis and an outer circumferential rotor boundary and impellers with vertical wind-receiving impeller surfaces, said vertical impeller surfaces:
(a) extending from the outer circumferential rotor boundary inwardly in a spiral path to absorb energy from the wind as it proceeds centrally into the core of the turbine, and (b) directing air that has followed the inward spiral path to proceed against the second vane and transfer its energy to the rotor, said turbine comprising:
(1) a surrounding circumferential series of vertically deployed deflector vanes mounted between upper and lower end plates that support the turbine rotor,

(2) each of said vanes being tubular in shape, widening from an edge at its outer circumferential boundary proceeding towards the turbine axis to a vertical surface constituting a base located at the inner boundary of each vane, said base being positioned next to the outer circumferential path of the turbine, CA 0222~42~ 1997-12-22 whereby air arriving from all directions is concentrated and directed against the turbine impeller surfaces to effect rotation of the rotor under the force of the wind.

Claims

I CLAIM:

1. A vertical axis turbine having a turbine rotor with a vertical axis and an outer circumferential rotor boundary and impellers with vertical wind-receiving impeller surfaces, said vertical impeller surfaces:
(a) extending from the outer circumferential rotor boundary inwardly in a spiral path to absorb energy from the wind as it proceeds centrally into the core of the turbine, and (b) directing air that has followed the inward spiral path to proceed against the second vane and transfer its energy to the rotor, said turbine comprising:
(1) a surrounding circumferential series of vertically deployed deflector vanes mounted between upper and lower end plates that support the turbine rotor, (2) each of said vanes being tubular in shape, widening from an edge at its outer circumferential boundary proceeding towards the turbine axis to a vertical surface constituting a base located at the inner boundary of each vane, said base being positioned next to the outer circumferential path of the turbine, whereby air arriving from all directions is concentrated and directed against the turbine impeller surfaces to effect rotation of the rotor under the force of the wind.