Rotating machine for interaction with a gas or liquid

The present invention relates to a rotor blade unit. The invention further relates to a fluid interaction device. The invention further relates to a power generator or an electric motor. The present invention further relates to a rotor blade.

Many different types of wind turbine are known. Each of these wind turbines has its own operating principle with specific advantages. The present invention provides a different operating principle with specific advantages not available in the prior art.

The present invention provides for this purpose a rotor blade unit, comprising at least a rotor blade or vane for realizing an energy conversion with a fluid medium, wherein the form of a rotor blade comprises the following characteristics that:

- it is spiral-shaped around a central axis,

- the blade extends substantially along the central axis from the central axis, and the blade is definable in a flat plane from which it can be transformed into the three-dimensional spiral shape.

An advantage of such a rotor blade unit is that an interaction with a medium is provided wherein an energy transfer is possible in a manner which hardly disrupts the fluid flow. A suction action is for instance provided with this rotor blade unit whereby the efficiency per area is relatively high. This suction action enables an operation wherein the efficiency is maintained even at an angle with the fluid flow. The rotor blade unit is further able to orient itself automatically, even without a wind vane.

In a first preferred embodiment each rotor blade is substantially definable within a circular form by means of defining a curve inside the circle which extends from substantially the centre of the circle to the edge of the circle, and a straight line which extends as a radial from the centre to substantially the intersection of the curve and the circumference, wherein the circle is divided into a rotor blade area and a cut-away area. An advantage hereof is a further improvement of the stated effects.

The ratio between the rotor area and the cutaway area is more preferably about two to one. Three rotor blades hereby provide the surface area of a hemisphere, this being a maximum ratio of a volume which can receive fluid relative to an area for converting energy.

In a further preferred embodiment each rotor blade in the rotor blade unit is membrane, sheet or plate-like. A large area is hereby possible relative to the used volume provided by the blade.

In a further preferred embodiment the rotor blade unit comprises a number of rotor blades, preferably three, which are arranged together along a shared central axis at an equal mutual angular distance relative to this central axis, wherein the blades spiral into each other with the spiral form when assembled. A greater efficiency can hereby be realized with one volume. A further advantage is that a greater stability is realized since pressure from the medium is distributed more uniformly over the periphery of the rotor blade

1 unit.

A further aspect of the invention relates to a fluid interaction device such as a wind turbine, marine engine or pump, comprising a rotor blade unit as claimed

in one or more of the foregoing claims, wherein the device comprises:

- a frame for supporting the device,

- an energy converter coupled to the frame for converting energy,

- a coupling between the rotor blade and the frame for supporting the rotor blade.

Using such a fluid interaction device a fluid interaction device becomes possible allowing the advantages of a rotor blade unit according to the present invention comprised in a fluid interaction device.

A further aspect of the present invention relates to a power generator or electric motor for providing a conversion between kinetic energy and electric energy, comprising:

- a rotor for rotation relative to a stator,

- a stator for allowing the rotor to rotate relative thereto so that a magnetic coupling therebetween can be applied during the energy conversion, wherein:

- the rotor comprises at least an array of sources for a magnetic field and the stator comprises at least an array of converters for the magnetic field into electrical energy, or this arrangement between the stator and rotor is reversed, which arrays are situated in a circular form and the rotor and the stator are arranged coaxially in order to provide a movement and variation in the magnetic field necessary for the conversion.

Using such a power generator or motor, the advantages of a rotor blade unit according to the present invention are combined with those of a power generator or motor.

In the power generator or electric motor according the previous embodiment, the direction of the magnetic field is preferably situated during use in the plane of the movement or substantially transversely of the direction of the movement.

In the power generator or electric motor the stator preferably comprises windings substantially in the plane of the rotation direction. The magnet pole ends are preferably also arranged at an angle relative to the direction of movement, preferably as seen in the length direction.

It is advantageous here when in the power generator or electric motor a number of stators or rotors are brought together in a module which can be arranged in repeated manner in the device.

A further aspect of the invention relates to a rotor blade according to one or more of the foregoing claims for application in a device according to one or more of the foregoing claims .

A further aspect of the invention relates to a method for obtaining energy by means of a device according to one or more of the foregoing claims, comprising steps for:

- providing the device,

- allowing the device to interact with a fluid. Further advantages, features and details of the present invention will be described in greater detail hereinbelow with reference to several preferred embodiments. Reference is made here to the accompanying figures, in which:

- Figure 1 is a view of a first preferred embodiment according to the present invention;

- Figure 2 is a view of the preferred embodiment similar to figure 1, with indicator lines;

- Figure 3 is a schematic side view of the embodiment of figure 2 in a position of use;

- Figures 4A-D are different views of the embodiment of figure 2;

- Figure 5 is a perspective view of a further preferred embodiment according to the present invention;

- Figure 6 is a cut-away side view of the embodiment of figure 5;

- Figure 7 is a perspective view of a part of the embodiment of figure 5;

- Figure 8 is a front view of the embodiment of figure 5;

- Figure 9 is a schematic side view of a further preferred embodiment according to the present invention;

- Figure 10 is a schematic side view of a further preferred embodiment;

- Figure 11 is a cut-away perspective view of a further preferred embodiment according to the present invention;

- Figures 12A-D are schematic views of a further preferred embodiment according to the present invention;

- Figures 13A-D are schematic views of a further preferred embodiment similar to those of figures 12A-D;

- Figure 14 is a schematic view of a component of a generator in a preferred embodiment according to the present invention;

- Figure 15 is a schematic view of a further preferred embodiment of the generator;

- Figure 16 is a schematic view of a further preferred embodiment according to the present invention;

- Figure 17 is a further schematic view of a preferred embodiment according to the present invention;

- Figure 18 is a further schematic view of a preferred embodiment according to the present invention;

- Figure 19 is a schematic view of a further preferred embodiment according to the present invention;

- Figure 20 is a perspective view of an embodiment similar to that of figure 19.

A first preferred embodiment according to the present invention (fig. 1) relates to a top view of a representation of a blade according to a first preferred embodiment according to the present invention. This is a blade definable on a plane which forms a curved surface in the position of use, wherein line 3 substantially forms a straight line around which the curved surface formed by surface 10 extends. The outside line 1 here circles round "axis" 3 several times. Figure 2 shows a representation of a further preferred embodiment of this blade definition, wherein several intersections of lines indicating dimensions are defined. In this preferred embodiment blade surface 10 is drawn around a coordinate system x,y. Curved line 3 extends in upward direction from the origin, curves downward to intersect the x-axis at a distance xl, which is H the distance x3, wherein x3 is the circumference of the circle formed by curve 1. Curve 3 intersects the y-axis at intersection yl, which is half the distance to the origin, and intersection y2 with circle 1. Curve 3 further intersects the x-axis at intersection x2, which, from the origin, is located at a distance of H of the distance x3 relative to the origin. Finally, curve 3 intersects the y-axis at point y2, which is just as far from the origin as point y. This almost mathematical representation of the area of the

vane blade in the flat plane can of course only be approximated in practice. According to this preferred embodiment the vane blade will thus have substantially this form, but will differ to the extent this is necessary from a production engineering viewpoint. Although this definition of the curve is only an example and this definition does not fully determine the curve, it is possible within the concept of the present invention that other curves exist which define a vane blade within the circle of curve 1, with an operation which falls within the present invention.

In the view of figure 2 straight lines are further drawn which are designated by means of Roman numerals I, II, III, IV. Curves are shown in the schematic side view of figure 3 in order to further elucidate the spatial orientation in the position of use. Edges 1, 3 and 7 are also shown in this figure 3 in order to indicate the position of these edges in the spatial form. Origin 2 is further shown as the outermost end of the blade in the spatial orientation. The other outermost point 4 is situated at the other end. Line 1 runs from point 2 to point 4. Line 7 runs from point 2 to point 5 and line 3 runs from point 2 to point 4 _λ this as also shown in the flat plane. For the purpose of elucidating the construction of a vane blade, it is shown in four different orientations in figures 4A-4D. Figure 4A relates to a side view, as does figure 4C. The difference here is a 90° rotation around the longitudinal axis of the vane blade. Figure 4B shows a perspective view of the vane blade. Figure 4D shows a front view. This clearly shows how in this preferred embodiment the number of rotations of the vane blade around central axis 3 is slightly greater than 3. In a determined preferred

embodiment the number of rotations of the frame blade round the central axis amounts to pi revolutions.

Figure 5 shows an example of an embodiment in which a vane blade as described in the foregoing is incorporated in a wind turbine. Three of these vane blades are here incorporated into this wind turbine 11, each of which are rotated 120° relative to central axis 13, which is formed by three of the edges 3 of each of the blades, for arrangement at an equal angular distance. The wind turbine is constructed around a rotor 12 which is arranged rotatably inside an outer ring 14. Forming part of the rotor is an inner ring 15 which is connected to rotor blades 16, 17 and 18 by means of fixing rods 19. The outer ring is mounted on a stand which can be constructed in many different ways. The stand serves for mounting of the whole on the ground or a building. The outer ring is mounted rotatably relative to the stand in a manner which is not shown. The skilled person will be able to propose a variety of bearing mountings for this purpose.

In this preferred embodiment of figures 5-8 a power generating unit is arranged inside the housing of outer ring 14. This annular dynamo is formed on the one hand by components 22 on the inner ring forming part of the rotor, which components for instance comprise permanent magnets, and is formed on the other by an array of stators which are arranged in the outer ring for the purpose of generating an electric current, and thereby electrical energy, under the influence of a variable magnetic field of elements 22 generated by the rotation. The operation of this dynamo is further explained below.

The inner ring is bearing mounted relative to the outer ring by means of wheels 24, which support

against a support body 25 of outer ring 14. This support body also houses the different components of the dynamo. This is shown in front view without the outer ring in figure 8. Wheels 24 are arranged here close to fixing rods 19, which serve as fixing of vane blades 16-18 on inner ring 15. Although the fixing of the blades to the generator is carried out in the above described preferred embodiment by means of an inner ring which encloses the blades at their widest point, an arrangement is shown in the embodiment of figure 9 in which blade unit 12 is mounted between a front bearing 34, which is supported by a front support, and a rear bearing which is incorporated in a generator unit 31. Such a generator unit is constructed in a manner which is analogous to that of a known wind turbine. Generator unit 31 supports on a generator support 32.

In a further preferred embodiment (fig. 10) blade unit 12 is likewise mounted on ring 37 encircling the blade unit, in this case comprising a possibility for driving an external generator 39. It is possible here to envisage a standard gear transmission from ring 37, via a gear 38 and a transmission shaft 40. In the latter two embodiments the blade unit is similar to that of previous embodiments, although the manner in which the energy is taken off corresponds more to known forms of wind turbine.

In the embodiment of figure 11 the vane blades are not per se self-supporting, but a rigid central axis 41 is provided which forms substantially a straight line within the blade unit. Three support spirals, which follow a curve substantially similar to edge 1 of the above described blades, extend in spiral form around central axis 41. These support spirals serve to provide a sup-

port to vane blades which are not rigid per se, i.e. for instance film material which is fixed between central axis 41 and spiral-shaped edge supports 42, 43, 44. Apart from this alternative construction, the vane blade unit has a construction similar to the embodiment of figure 5.

A first preferred embodiment of the dynamo (fig. 12) is shown in four different views. Figure 12A is a top view. Figure 12B is a cut-away perspective view. Figure 12C is a front view and figure 12D is a side view. The generator as a whole is a ring core generator. In such a generator the conversion of kinetic energy to electric energy is carried out under the influence of a change in the strength of a magnetic field during the movement. In this case the alternating magnetic field is produced by the movement of the large number of permanent magnets of the rotor inside the windings of the stator. An advantage is gained here in this preferred embodiment by enlarging the area by increasing the length of the contact surface in the oblique arrangement of air gap 50 between the stator and the rotor. By way of clarification, the rotor is here part of inner ring 15 of the wind turbine and the stator is part of outer ring 14. The view of figure 13 shows an alternative arrangement wherein use is also made of the oblique arrangement, whereby a greater area of the gap is achieved. It hereby becomes possible to keep the magnetic resistance in the air gap as low as possible, with the result that a lower number of windings is required to achieve the same field strength. The increase in surface area achieved by a 45° arrangement of the gap is substantially a factor V2. The large number of poles of the rotor and the large number of stators around the pe-

riphery of the generator ensures that a voltage can be generated along the whole periphery. The rotor poles herein alternately change direction. An alternating magnetic field can hereby be generated, whereby a voltage can be induced. The stators preferably also alternately change pole direction, whereby a voltage with the same direction will be induced in the conductor. As shown in figure 14, the contacts are connected for this purpose in crosswise manner so that the polarization of successive stators reverses. Figure 14 shows a three-phase system wherein the fixed magnets of the rotor move along three-phase polarized stators with a mutual phase shift which is per se known. This whole will be arranged in practice in the generator in an arcuate form in order to follow the circular form of the generator.

Figure 5 shows the overall form of the magnetic field per stator.

Figure 19 shows a single-phase helical winding as a preferred embodiment according to the present invention. Stator poles A-F are shown in the rotation direction of the rotor. The rotation direction of the rotor is here in the direction of arrows K. Stator poles 1-8 are shown transversely of the rotation direction of the rotor. Conductor LA runs through stator pole IA and is then guided through stator poles 2B, 1C, 2D, IE, 2F, A3, B4, C3, etc. until it leaves the stator pole assembly at 8F. Conductor LB runs from stator IF to stator A8 in the same way. Together the shown stators form stator module 60. Such modules can be coupled to each other in order to form the stators of the outer ring. A stator block of a greater capacity can hereby be obtained by means of standard modules. It is also possible to manufacture multi-phase standard modules which function

analogously to the multi-phase winding shown in figure 14.

The magnetic operation of the generator according to the present invention is further elaborated in figures 15-18. Numeral 62 in figure 15 designates the rotor field coil of the permanent magnets. Numeral 63 designates the magnetic field direction. Numeral 64 designates the magnetic field direction as a result of the current when the generator is in operation. In figure 16 numeral 65 designates the magnetic force field as a result of the rotor pole. Numeral 66 indicates the magnetic force field resulting from the current through the stator conductor.

In figure 17 numeral 72 indicates that the parts of the rotor round the magnets and the parts of the stator round the windings comprise a magnetically conductive material. Numeral 71 designates the permanent magnet or field coil of the rotor. A field coil in a rotor is an alternative to the permanent magnet, which can be applied subject to requirements. In figure 18 numeral 74 designates the field winding of the rotor, the force F of the magnetic field is designated by means of the associated arrows. Reference numeral 73 designates the stator conductor.

Figure 20 shows a perspective view of an arrangement similar to that of figure 19. The construction of the stator units in the outer ring is hereby shown in a more spatial manner.

Several further alternative exemplary embodiments are referred to hereinbelow on the basis of the structural measures described above in the preferred embodiments. The application of three vane blades provides a surface area of vane blades equal to the surface area

of a hemisphere. The reason herefor is that in a preferred embodiment the surface area 10 of a rotor blade amounts to 2/3 of the total surface area of the substantially circular part within outer edge 1. The same area is hereby utilized as the maximum area of a volume per surface area, i.e. that of a hemisphere. It must be understood here that in practice such ratios can only be approximated or aimed for. In the different embodiments the blade unit can be embodied by means of a ring suspension, for instance by means of wheels or ball bearings. The front side close to point 4 and the rear side close to point 2 can here be embodied without support as well as being provided with a support. As wind turbine, the point 4 is arranged in the direction of the wind. A self-orienting capacity is also achieved by the present construction, whereby the "nose" of the device will orient itself toward the wind if the wind changes. Further achieved is that the power of the device will not decrease, even when the wind direction changes within a certain margin of at least 20°, and will even increase.

This invention further relates to a rotating machine, both of driven and driving type, which can be used as for instance a pump, compressor, generator, drive motor, wind or water turbine and so forth. The machine is preferably not of the positive displacement type. A rotating machine of the positive displacement type is for instance a piston pump. The machine is intended for interaction with a fluid medium such as a gas or liquid.

The medium flows through and/or around the machine.

At the moment a machine driven by wind or water or other liquid or gaseous medium, for instance for gen-

erating galvanic or other energy, is deemed an important application of the invention. It must however be apparent that the invention can be applied in any conceivable field, for instance as propulsion for an air or water vehicle.

This machine has many advantages, including being bird-friendly and having a high energy efficiency.

The machine comprises a rotor with which energy is extracted (such as for instance with a wind turbine) from or relinquished (such as for instance in a compressor or pump) to the fluid medium. For this purpose the rotor has one or more blades (or is formed thereby) which interact with the medium and around which the medium for instance flows, and is rotatable around a fixed centre point through which the preferably straight (optionally physical) rotor axis runs.

The rotor is preferably coupled drivingly to an energy take-off device such as a generator or an energy supplying device such as a drive motor.

Among the one or more blades is a blade which extends helically or spirally along the rotor axis and the projection (also referred to as the thread) of which forms in the flat plane a substantially continuously narrowing strip spiralling around a centre point. One or more of the following aspects preferably apply to the strip in the projection:

- one or more side edges of the strip follow a line curving around the centre;

- a side edge of the strip maintains a substantially fixed distance (for instance radius) to the centre point;

- the strip has no overlap;

- the strip makes at most, or precisely, a single rotation around the centre point/

- a side edge of the strip maintains a continuously increasing distance (for instance radius) to the centre point;

- a side edge of the strip has a distance of substantially zero to the centre point;

- the surface area of the strip is such that the surface area of three identical strips is substantially equal to half the surface area of a sphere with a radius equal to the maximum distance from a side edge of the strip to the centre;

- the beginning and/or end of the strip is removed.

This blade can be made by moving both ends of the flat strip apart along the rotor axis, i.e. the axis perpendicular to the plane in which the flat strip lies. The strip is preferably twisted here, i.e. rotated around the rotor axis or an axis parallel thereto. The tip or zone of an end closest to the centre point is preferably kept a fixed distance from the centre point or straight line (for instance rotor axis) therethrough.

The blade preferably has a substantially constant pitch along its length, i.e. the blade spans a fixed distance along the rotor axis per unit of rotation around the rotor axis. The pitch preferably relates to the imaginary line which extends between the ends of the strip and maintains equal distances to the side edges of the strip. The blade preferably extends over a length along the rotor axis, determined by:

- more than its maximum strip width,

- more preferably more than two or more than 2.5 times its maximum strip width; and/or

- more than its single or double maximum diameter; and/or

- more than the single maximum diameter of the circle described by its strip.

The blade preferably makes more than a single, more preferably more than two or more than 2.5 rotations around the rotor axis. Along a part of its length the edge of an outer end of the blade preferably maintains a distance to the rotor axis.

Going along the rotor axis the outer diameter of the blade preferably increases continuously up to a maximum. Seen in side view, the blade preferably has a substantially funnel-shaped, cone-shaped or tapering outer end. The end with cone shape and/or greater diameter is preferably situated on the downstream side of the fluid medium.

The blade preferably has a substantially smooth and/or continuous form.

When applied as wind turbine the blade substantially fully captures the wind flowing in substantially parallel to the rotor axis and allows it to escape laterally (relative to the rotor axis) at its downstream funnel-shaped end, for instance along the end maintaining a distance from the rotor axis.

The rotor preferably comprises two, three or more of these blades, which are preferably nested in each other and preferably have substantially equal angular distances relative to each other around the rotor axis. The rotor preferably comprises only these blades.

These blades are preferably relatively thin compared to their length and width. They have for instance the form of a membrane, sheet or plate. They can be made from any suitable material, for instance metal or plas-

tic or composite. Envisaged at the moment is a layered material of alternately metal plate and layers of fibre- reinforced resin, for instance of the type known under the brand name GLARE (many thin aluminium plates interleaved with glass fibre-reinforced resin of construction quality, for instance epoxy) .

A preferred embodiment (fig. 1) of a blade for the machine as a wind turbine can be obtained by making a strip of sheet-like material with the form shown in the drawing. Of the strip lying in the plane of the drawing, the one side edge 1 describes a circle with centre point 2. The other opposite side edge 3 begins in centre 2 and has a spiral shape with continuously increasing radius to the centre. Both side edges 1, 3 make a single rotation of 360 degrees around centre 2 and gradually come closer together and meet at outer end 4.

The blade can be formed by fixing its edge 3 at centre 2 to the straight rotor axis (not shown) running perpendicularly of the plane of the drawing and fixing end 4 to the rotor axis at sufficient distance from centre 2, wherein the strip rotates around the rotor axis. At outer end 5 of side edge 1 which is opposite to end 4 the strip is also moved out of the plane of the drawing in the same direction as end 4 and parallel to the rotor axis in order to cause the outer end of the strip to end at centre 2 in a smooth funnel widening in upstream direction. Outer end 4 is optionally co-rotated around the rotor axis with the pitch.

In the three-dimensional form of the blade the distance between points 2 and 4 amounts to about 1.5 times the diameter of the circle described by side edge 1, while point 5 is situated on a radial line from the rotor axis through point 6, wherein points 5 and 6 main-

tain a gap so that the funnel-shaped end forms a substantially tangential outflow gap running along the end edge I ₁ which has remained substantially straight. In a variant one or both ends of the strip can be omitted.

Machine as according to the foregoing, wherein the blade is made by moving apart the two ends of the flat strip along the rotor axis, wherein the strip is preferably twisted here.

Machine as according to the foregoing, wherein the tip or zone of an outer end of the strip closest to the centre is preferably held a fixed distance from the centre or straight line therethrough.

Machine as according to the foregoing, wherein the blade has a substantially constant pitch along its length and/or a substantially smooth and/or continuous form.

Machine as according to the foregoing, wherein the blade extends through a length along the rotor axis, determined by:

- more than its maximum strip width, preferably more than two or more than 2.5 times its maximum strip width; and/or

- more than its single or double maximum diameter; and/or

- more than the single maximum diameter of the circle described by its strip.

Machine as according to the foregoing, wherein the blade makes more than a single, preferably more than two or more than 2.5 rotations around the rotor axis and/or the edge of an end of the blade maintains a distance to the rotor axis along a part of its length.

Machine as according to the foregoing, wherein, going along the rotor axis, the outer diameter of the

blade increases continuously up to a maximum, and/or the blade as seen in side view has a substantially funnel- shaped, cone-shaped or tapering end which is preferably situated on the downstream side of the fluid medium.

The present invention is described in the foregoing on the basis of several preferred embodiments. Different aspects of different embodiments are deemed described in combination with each other, wherein all combinations which can be made by a skilled person on the basis of this document should be included. These preferred embodiments are not limitative for the scope of protection of this text. The rights sought are defined in the appended claims.