GB2512114A - A drag-type wind turbine - Google Patents

Abstract

A drag-type wind turbine 10 comprising an axle and cups 40, where each cup is coupled to the axle 20 such that the wind incident on the cups is at an angle substantially non-parallel to the axle and causes the axle to rotate. The cups have a substantially conical shape, which may be a right conical shape or an oblique conical shape. The cups may be arranged such that the centre of the base 50 and the apex 60 of each conical lie substantially on the perimeter of a circle centred on the axle and wherein the cups may be arranged such that imaginary straight lines connecting the centre of the base and the apex of each conical form tangents with the perimeter of a common circle 70 centred on the axle. A method of capturing energy from wind is also claimed.

Description

A DRAG-TYPE WIND TURBINE

The present invention relates generally to a drag-type wind turbine and a method of capturing energy from wind and finds particular, although not exclusive, utility in vertical-axis wind turbines.

Drag-type wind turbines are well known. One known arrangement is the Savonius wind turbine, invented by Sigurd johannes Savonius in 1922. A Savonius wind turbine comprises two or three scoops (i.e. bodies having one open side and one dosed side) that experience less drag when moving through air with their closed side lO leading than when moving through air with their open side leading. The scoops are mounted, equally spaced, about an axis such that the differential drag causes the turbine to rotate.

Another known arrangement is the cup anemometer, invented by John Thomas Romney Robinson in 1846. A cup anemometer comprises three or four hollow hemispherical cups each mounted, equally spaced, about an axis on one end of respective arms. The differential drag of tEe cups causes the turbine to rotate. The ratio of the speed of the wind to that of the cups, depends on the dimensions of the cups and antis.

Drag-type wind turbines such as these extract less power from the wind than similarly sized lift-type wind turbines. Developers of wind turbines for capturing wind power and converting it into electrical power have therefore focussed on llft-type wind turbines and, specifically, horizontal-axis wind turbines.

However, drag-type wind turbines and, specifically, vertical-axis wind turbines have certain advantages. For instance, they can be more stable, they can function independent of wind direction, and they may he considered less intrusive in a natural environment. For instance, they appear to a distant viewer as moving laterally, rather than appearing to a distant viewer as rotating, which is a movement not observed in nature. Furthermore, the diameter of the turbine may he increased arbitrarily large, without a need to increase the height of the turbine, thereby causing less environmental impact.

The present invention therefore seeks to improve on known designs of drag-type wind turbines, in order for them to be considered for use in electrical power generation.

I

According to a first aspect of the present invention, there is provided a drag-type wind turbine, comprising: an axle; and a plurality of cups, each coupled to the axle such that wind incident on the cups at an angle substantially non-parallel to the axle causes the axle to rotate; wherein the cups have a substantially conical shape.

Conical shape' may mean a 3-dimensional geometric shape that tapers smoothly and/or uniformly from a closed-curve shape base to an apex. The conical shape may therefore comprise a base and an apex-forming wall. The closed-curve shape may be a circle, an ellipse, an oval, or other closed-curve shape. The conical shape may he a circular conical shape. The closed-curve shape may be free of concave portions.

lO Alternatively, the closed-curve shapc may include one or more concave portions. In some embodiments, the conical shape may be a truncated conical shape.

In this way, drag experienced by the cups when moving through air with their apex-fomiing wall leading may be reduced compared to hemispherical shape cups. In addition, turbulence caused by air passing around the cup from the base to the apex-forming wall may he reduced, thereby increasing wind pressure on adjacent cups and decreasing stress on the axle.

The conical shape may be a right conical shape; that is, having an axis that ptsses through the apex anti the centre of the base substantially at right angles to the base.

Alternatively, the conical shape may be an oblique conical shape; that is, having an axis that passes through the apex and the centre of the base at an angle that substantially differs from 90 degrees to the base.

The cups may be arranged such that the centre of the base and the apex of each conical shape lie substantially on the perimeter of a circle centred on the axle. In this way, the apex of a leading cup may he arranged to channel wind toward the base of a following cup. The apex of a leading cup may he inside a following cup Alternatively, each cup may he spaced from each adjacent cup by a predetermined distance.

Alternatively, the cups may be arranged such that imaginary straight lines connecting the centre of the base and the apex of each conical shape form tangents with the pcrimeter of a common circle centred on the axle.

The cups may have an open side and/or a closed side. In particular, die open side may comprise the base of the conical shape and die closed side may comprise the apex-fonring wall.

The apex angle of the conical shape may be between approximately 10 degrees and 90 degrees. The apex angle of the conical shape may he between approximately 15 degrees and 60 degrees. The apex angle of the conical shape may be between approximately 20 degrees and 45 degrees. The apex angle of the conical shape may he between approximately 25 degrees and 30 degrees. Tn particular, the apex angle of the conical shape may be approximately 23 degrees or 30 degrees. The apex angle may be defined as the maximum angle at the apex inside the apex-forming wall.

The drag-type wind turbine may comprise 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 cups.

The cups may be equally spaced from one another and about the axle.

lO Each cup may be coupled to the axle via a respective arm. Each arm may be attached to the respective cup at a point substantially adjacent the base of the conical shape. Alternatively, each arm may he attached to the respective cup at a point spaced from the base of the conical shape and the apex of the conical shape.

The size of the cup may he chosen by varying the sL'e of the base of the conical shape, or varying the size of the apex angle of the conical shape. The length of each arm may he varied dependent upon the sie anti the number of cups.

The turbine may be made from any conventional material, such as metal alloy, aluiiilni urn, composite material arid/or carbon fibre.

The turbine may have a diameter of between approximately 10cm and BOrn. In particular, the turbine may have a diameter of approximately 20m.

According to a second aspect of the present invention, there is provided a method of capturing energy from wind, comprising: providing a drag-type wind turbine according to the first aspect; selecting a location for the turbine to receive wind; and allowing the axle to rotate in response to wind incident on the cups at an angle substantially non-parallel to the axle.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without hmiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Figure 1 is a first embodiment of the present invention having 8 cups.

Figure 2 is a second embodiment of the present invention having 6 cups.

The present invention will be described with respect to parttcular embodiments and xvith reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the sii.e of some of the elements may he exaggerated and not drawn to scale for ill ustrative puoses. The dimensions and the relative (Ilmensions do not correspond to actual reductions to practice of thc invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It lO is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to he understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to he noticed that the teriti comprising'', used iii the claims, should riot he interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or componcnts as referred to, but does not preclude the presence or addition of one or more other features., integers, steps or components, or oups thereof. Thus., the scope of the expression "a device comprising means A and 13" should not he limited to devices consisting only of components A and 13. It means that with respect to the present invention, the only relevant components of the device are A and B. Similarly, it is to he noticed that the term "connected", used in the description, should not he interpreted as being restricted to direct connections only. Thus, the scope of the expression "a device A connected to a device B" should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may he a path including other devices or means. "Connected" may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other.

Reference throughout this speciticatinn to "one embodunent" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, hut may refer to different embodiments.

Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly, it should he appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to he interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claitTi. Rather, as the following clairris reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, xvhile some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to he within the scope of the invention, and fonn yet further embodiments, as will he understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can he used in any combination.

In the description provtdcd herein, numerous specific details are set forth.

Ilowever, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of

this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indicatlim that one of said values is more highly preferred than the other, is to he construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term "at least one" may, in some embodiments, mean only one.

The invention \vill now be described by a detailed description of several lO embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

Figure 1 is a plat view of a drag-type wind turbine 10 according to the present invention. The turbine tO comprises an axle 20 and eight arms 30 extending out from the axle 20. Each arm 30 may he a single rod, which may he relatively light-weight.

AJternattvely, each arm 30 may be one half of a rod that extends across the axle 20 from one side to the other.

At the end of each ann 30 is a cup 40. Each cup 40 has a substantially conical shape, shown in the figure as a triangle due to the plan view. In particular, each cup 40 has a substantially right circular conical shape. Each arm 30 is attached to the respective cup 40 adjacent an open circular base 50.

Imaginary straight lines passing at right angles through the circular base 50 and through the apex 60 of each cup form a tangent xvith an imaginary circle 70, centred on the axle, and shown in the tigures as a dotted line.

Figure 2 is a plan view of another drag-type wind turbine 15 according to the pese' invention. The turbine tS comprises an axle 20 and six anns 30 extending out from the axle 20.

At the end of each ann 30 is a cup 45. Each cup 45 has a substantially conical shape, shown in the figure as a triangle due to the plan view. In particular, each cup 45 has a substantially oblique circular conical shape. Lach arm 30 is attached to the respective cup 45 adjacent an open circular base 50.

Imaginary straight lines passing at right angles through the circular base 50 of each cup form a tangent with an imaginary circle 70. The circu'ar base 50 of each cup and the apex 65 of each cup lie on the perimeter of an imaginary circle 70, cenfted on the axle, and shown in the figures as a dotted line. This arrangement of the apexes 65 with respect to the circular bases 50 assists channelling wind into the open circular bases 50.