DEVICE FOR HARNESSING WIND ENERGY

Abstract: Device for harnessing wind energy, comprising a number of propeller elements which are fitted rotatably on a rotary shaft which is coupled or can be coupled to an electricity generator situated in the housing, the housing being pivotable about a vertical axis. The propeller elements (14) are pivotable about tangential axes relative to a slide (36) which is slidable along the shaft (13), and that they are provided with means (37, 38) for holding them in an angular position relative to the shaft and for altering that angular position. Preferably the means for holding and altering the angular position of the propeller elements (14) comprise bars (38), one end of which is hingedly fixed on an intermediate point along the length of the propeller elements, and the other end of which is hingedly fixed to a second slide (37) which is slidable along the shaft. Also preferably the propeller elements (14) in their fully collapsed position, in which they form a minimal angle with the shaft, are situated at least with the greater part of their length in a chamber in the housing (2). Most advantageously the housing (2) is designed as a ship which is disposed so that it pivots relative to the seabed.

Description: Title: Device for harnessing wind energy. The invention relates to a device for harnessing wind energy, comprising a number of propeller elements which are fitted rotatably on a rotary shaft which is coupled or can be coupled to an electricity generator situated in the housing, the housing being pivotable about a vertical axis. One of the major disadvantages of such devices, generally called wind turbines, is that the power is limited. Limits are set, on the one hand, by the strength of the vanes and, on the other, by the strength of the mast or tower on which these turbines are mounted. The main problem lies not so much in a higher average wind speed, but in the fact that high wind speeds are increasingly accompanied by strong gusts. In this connection account has to be taken of the fact that wind pressure increases quadratically with the speed. It is known to reduce the influence of threatening gusts and storm by altering the pitch angle of the vanes, working with or without the use of a regulator with a set of centrifugal weights. With increasing wind the speed of rotation is thus reduced by adjusting thr pitch angle to turn them in the end completely parallel to the wind, so that the turbine stops. The risk of damage to the vanes through storm is not, however, totally eliminated by this (consider the changeable nature or the wind direction) , and the great moment which is exerted on the tower by the wind pressure on the housing of the turbine also unavoidably remains. The object of the invention is therefore to make proposals by means of which a very considerable increase in scale can be applied in the designing of a wind turbine through the fact that the dimensioning is no longer subject to limitations of the existing turbines. Characteristic of the device according to the invention is the fact that the propeller elements are pivotable about tangential axes relative to a slide which is slidable along the shaft, and that they are provided with means for holding them in a set angular position relative to the shaft and for altering that angular position. In this way, from a working position which is suitable for normal working weather, i.e. up to a certain wind force, the vane rotor can at any moment be given an altered position by means of which the cross-section of the flow tube is reduced. The cross- section of the flow tube decreases quadratically with the diameter thereof and thus constitutes a first compensation for the wind pressure increasing quadratically with the wind speed when the latter increases. As higher wind speeds arrive, the folding- in of the vanes can constantly go further until they rest virtually against the shaft. They are then preferably accommodated simultaneously with the greater part of their length in a chamber in the turbine housing. In all intermediate positions the turbine can then still turn further normally in order to derive the maximum possible power from the wind. Since the power of the wind is associated with wind speed according to a cubic function, a slight increase in the so-called "smoothening limit" of a wind turbine is already of great influence on the power to be taken up. An increase in the current smoothening speed on land of 13 m wind speed per second to e.g. 18 m/sec, as the limit at which according to the invention a start is made with levelling off of the power uptake through retraction of the vanes, therefore means an increase of up to 270% in the power. These stronger winds blow, of course, less frequently, but according to the invention a very considerable increase in the power is still achieved. A further important measure according to the invention for eliminating the limitations of the known technology is formed by the proposal to place the shaft of the turbine at an angle with the horizontal, rather than horizontally (and thus necessarily on a mast) . Such an angle is preferably around 35'. The housing would then be fitted with one end on a vertical shaft so that it pivots relative to an anchorage on the ground, so that it can always function under the wind. When this idea is realized on land, a limitation is very soon encountered in the form of the large dimension of the pivoting circle which then has to be kept free for the turbine. Yet another increase in scale can be used if the housing is designed as a ship which is fitted so that it pivots relative to the seabed, in which case the axis of the housing is then also placed at the above- mentioned angle of 35' relative to the horizontal. This can be achieved simply by means of the floating power which the housing has as a ship. A large number of design problems which would be encountered with placing on land (a support with a rotary device) are also solved in this way. The ship will rotate by itself with the rest and remain lying in the bottom. In the case of the proposed angle of 35', which is preferable, inter alia, from the point of view of aerodynamic considerations, as will be explained in greater detail below, it can be said, broadly speaking, that in this way a vane length (thus the radius of the vane rotor in the folded-out position) which is approximately equal to the depth of the sea at the place where the turbine ship will be anchored can be used. To be more specific, for a sea depth of 100 m this gives an admissible value of 200 m for the diameter of the vane rotor. Using the different proposals according to the invention, there are no reasons for concluding that such dimensions would not be realistic. On placing in the sea, every advantage can already be directly achieved from the known fact that the average wind speeds at sea are considerably higher than on the coast or on land. According to the Royal Netherlands Meteorological Institute, the annual average wind speed above the interior (in the country) is 5 m/sec, above the coast 6 1/2 m/sec, and above the sea 9 m/sec, all this measured at a height of 10 above the ground or sea level. If the rotor can be given a diameter of 200 m or more, it is also possible to make use of the fact that the average wind speed increases constantly at a greater height. The same series of observations as those just mentioned includes the observation that at 100 above sea level the average speed is already 10.84 m/sec. As was already pointed out earlier, this higher speed has a third power influence on the power contained in the wind. The device is also advantageously carried out in such a way that the propeller elements together with a cage comprising at least three bars are rotatable relative to the housing, while the shaft is essentially stationary relative to the housing. The large scale in the design of a wind turbine achievable according to the earlier summarized idea of the invention gives cause for a further regulation facility. The whole unit can in fact be designed in such a way that a cog wheel is connected to the cage, along which the multiplicity of generators which can be brought into engagement individually with the cog wheel are set up. Switching off or switching on further generators is an action which in the first place is very simple in terms of control engineering, but can also be carried out with a very short response time. This gives the opportunity of not only reacting very flexibly and rapidly to variations in the wind speed in a short period, but also of doing this in such a way that the speed of rotation of the turbine is always maintained at a value which delivers the greatest overall useful effect from the energy conversion. Put more simply, switching on further generators can prevent the turbine from running away with increasing wind. Only in the second instance then is the remedy used where the angular position of the vanes relative to the shaft is gradually reduced and the vane rotor is finally retracted fully into the housing. The term "propeller elements" initally used above has already been replaced a number of times by the more commonly used term "vanes", and the whole of the propeller elements together is indicated for short as the "rotor". In the context of the present invention the term "propeller elements" should be understood as all wind-catching elements such as simple vanes, thickness profiles, windbreaks, rotors, whatever they are called, both rotary and moving otherwise in the wind, for the purpose of generating energy, and also all elements which are intended for concentrating the wind or for spreading the wash, such as the so-called tip vanes, funnels, fixed wall air distributors and such means which are for the purpose of directly or indirectly increasing the delivered power. It is also pointed out that in connection with the present invention all design measures which are known per se from aerodynamics, and in particular from wind turbine technology, can be used, as already indicated implicitly in the definition of the basic term "propeller elements" just given. Let us conclude this introduction to the description with the enumeration of a small number of special advantages of the proposals according to the invention. The vanes are now no longer all fixed at the bottom to the vane root, but also by the bars of the unfolding mechanism which acts on points lying in between. The vanes can easily be made self-yielding, in other words, in the event of unforeseen fierce gusts, such as those which occur particularly in the case of stronger wind, they can fold together parallel along the bar. Insofar as the turbine is designed as a ship, the seawater acts as a shock absorber for all gusts. The natural vibration of the plant occurring on land when turbines placed on masts are used is completely throttled in this way. In addition to the storage facility for the vanes during storm, the hold of the ship can also be used for auxiliary equipment such as pumps, transmission and coupling equipment, control and regulation instruments, servomotors, a transformer of the generated voltage, balancing and ballast tanks etc. Size limitations of turbines according to the invention designed as a ship - which can simply be called wind ships - seem not only unnecessary, but are even undesirable for similar reasons to those which led to the construction of very large ocean¬ going ships. Where they are designed as ships, the increased size will certainly not make the costs of transport and fitting of parts unacceptably high, as is often the case with plants on land. Wind ships according to the invention can in fact be built and equipped fully at shipyards where all the necessary requisites are permanently present for towing subsequently to the place of erection. The invention will now be explained in greater detail with reference to the appended drawing of an example of an embodiment in the form of a turbine which is designed as a wind ship which is anchored relative to the seabed. Figs. 1 to 4 show the successive stages of the unfolding of the vanes, from a fully collapsed position in which the vanes are for the most part situated in the housing to an unfolded state in which the vane rotor is situated at the furthest point away from the shaft, with an angle of 90' between each of the individual vanes and the shaft direction. Fig. 5 shows schematically the power ship in more detail, in the form of an axial section. Fig. 6 shows the guide mechanism for the mast, as a partial axial section; and Fig. 7 is a corresponding view as indicated by the arrow VI in Fig. 5. Fig. 8 shows a cross-section through the mast on a larger scale. Figs. 9 and 10 show the vane slide in a view in the radial direction and in side view respectively, in a direction at right angles thereto, but in this case leaving out the mast. Figs. 11 and 12 show details of the spreading slide in a view in the radial direction and * a bottom view respectively. Fig. 13 shows the slide opener. Figs. 14 and 15 show the vane position corrector, in a view in the radial direction and in the axial direction respectively. Fig. 16 shows separately a vane with a spreading bar seen in side view, and Fig. 17 in front view. Figs. 18 and 19 show the bar mechanism for the coupling between the vanes and the power ship from two directions at right angles to each other. Figs. 20 to 22 show a variant of an embodiment of the design which permits pitch adjustment of the vanes, in an axial view, a radial view and a side view at right angles to the radial direction respectively. Fig. 1 shows an embodiment of the device as a ship, indicated in its entirety by 1. The bottom part or lower ship 2 has the shape of a very slight, almost cylindrical, truncated cone. The axis 3 thereof forms an angle α of 35' with the surface of the sea. By means of four chains such as 4, which are connected at equal intervals to the outer periphery of the bottom, the wind ship is anchored to concrete caissons such as 5 which are lowered onto the seabed 6. The chains must have sufficient play for the rising of the ship under the influence of ebb and flow, and the ship swinging along with the wind direction must turn back so far that no torsion is produced in the electricity cable 7 from the ship to the land. Wave movements will hardly play any role in the position of the ship, in view of the envisaged large dimensions of the ship, and they will also be slowed down by the spinning action (gyroscopy) of the turning upper ship and the turning vanes. The floating power of the body of the lower ship 2 can be determined in such a way that with the combined hinge connection at the end the ship sets the desired angle of gradient α by itself. The angle α preferably has a value of 35'. The shape of the lower ship 2 will be determined on the basis of design considerations and on the basis of standards set with regard to the internal space rather than on the basis of hydrodynamic considerations. For the ship is installed at a fixed point and thus does not need to be streamlined like a sailing. Some streamlining in the form of rounding off of angles and similar measures can be desirable in order to reduce forces on the anchoring insofar as the ship is installed at a place where the sea shows some flow. The main shape will thus be slightly conical, because the main function of the hull is to form a storage space for the vanes which can be moved in a collapsed state along a shaft. For this, the lower ship 2 has a cage structure which is indicated in its entirety by 8, and which is formed, inter alia, by one or more bars 9 which are connected at the top, as indicated at 10. The cage is rotatable relative to the lower ship 2. The end of the mast or shaft 13 is fixed in a top bearing 12. The other end of the shaft is fixed so that it is substantially stationary in the lower ship 1 in a manner to be described further below. The mast 13 serves to guide the vanes during unfolding and folding up again. Fig. 1 shows the vanes 14 in the collapsed position in which they lie with the greater part of their length in the hold of the lower ship. Various stages of the unfolding of the vanes can be seen in succession in Figures 2 to 4, Fig. 4 showing the position in which the vane rotor 14 is situated at the end of the shaft in a position at an angle of 90' relative to the shaft direction. Figs. 1 to 5 show only two bars 9 of the cage structure, and also only two vanes 14, because this is easy to show and also easy to understand. For structural reasons, the cage structure 8 will have to comprise at least three bars 9. It is then a matter of course also to use three vanes, which is an advantage from the point of view of aerodynamic performance. For the description, it will, however, be assumed for the time being that there are two vanes. Fig. 5 shows a schematic axial section through the power ship, in the same vane position as Fig. 4. The body of the lower ship 2 is shut off at the bottom side by a simple flat end wall 15. On the outside thereof the necessary four eyes 16 are fitted for the anchoring. A bearing column 17 is fixed inside centrally on the bottom 15. This bearing column bears in the first place the bottom bearing bush 18 for the rotatable upper ship, through the fact that the bottom 19 of said upper ship is supported by it. Said bottom 19 forms the bottom seal of the ship's wall 20 of the upper ship. It can be seen that the bars 9 from which the cage of the upper ship is composed run through along the inside of said wall 20, as indicated by 9' , it being possible in principle to weld them over their entire length to said wall. The wall 20 of the upper ship is extended at the bottom past the bottom 19 in order to permit fixing of the central cog wheel 21 thereon. It will be clear that this cog wheel 21, the wall 20 of the upper ship and the wall 2 of the lower ship are coaxial. Pinions 22 of a number of generators 23 set up around the bearing column 17 on the bottom 15 of the lower ship are in engagement with the central cog wheel 21. Electrical couplings (not shown) are present to connect the individual generators to the cog wheel 21 when the latter is. turning. Annular balancing tanks 24, 24' are fitted in the top and in the bottom of the lower ship in order to ensure that the correct position of the power ship is maintained in all positions of the vanes. Bearing rollers, by means of which the upper ship is rotatably supported at the top side in the lower ship, are indicated by 26. Above that the hull 2 of the lower ship is provided with an inward-directed flange edge 27 over the top of which a flange edge first directed outwards and then directed downwards again is fixed to the hull 20 of the upper ship, which means that the hold of the lower ship is protected against rain and seawater. The shaft or mast 13 is in principle stationary relative to the lower ship, and the cage and the vane rotor rotate about it. It can be seen that the ship's wall 20 of the upper ship is cylindrical, that the hull 2 of the lower ship narrows slightly downwards in a conical shape, and that the cage composed of the bars 9 tapers conically upwards to a somewhat greater extent. At the top said bars - which in practice can also be tubes with in cross-section a propeller element shape and slightly twisted on lift in order to reduce friction relative to the wind and wind shadow - are connected in the already mentioned manner at 10, while 12 is also the already mentioned top bearing of the mast 13. The vanes 14 of a power ship are raised and spread in the wind by a system of two slides, namely the vane slide 36 (with slide opener and vane position corrector) , and the spreading slide 37 (with spreading tubes and regulation arms) . The two slides can move together along the mast 13 in order to take the vanes to the correct height and spread, and they are interconnected by the vanes and spreading tubes 38. The vane slide 36 is the uppermost of the two slides and bears on the rotary central part the vane position corrector 39 (to be discussed below) on which the vanes are fitted. The front and rear sides of the vane slide do not turn with the rest, but move along the mast by means of bearing rollers. In the front side there is a gearbox 40 which is driven by a servomotor. The gearbox drives gear wheels which convey the slides upwards. The spreading slide 37 is situated on the mast 13 below the vane slide. Only the central part of this slide also is rotatable. The front and rear side ensure rolling along the mast. As already pointed out, the mast 13 is in principle stationary relative to the lower ship. For a reason which will be described further below, it is, however, important that the mast always maintains the same position relative to the vertical, even if the ship in its entirety turns about its axis slightly in the water. For this purpose, the invention proposes a mast directing mechanism which is shown in detail in Figs. 6 and 7. Fitted in the bearing column 17 is a bush-shaped projecting part 25' of a supporting arm 25, which supporting arm bears a worm 29 driven by a motor 29'. Said worm interacts with a worm disc 30 which by means of a (read: pressure) bearing 30' and a centring pin 30" is rotatable relative to the bush 25'. The mast 13 is firmly connected to the worm disc 30. A bearing arm 32 for a balancing weight 33 is fitted in the mast 13 by means of a bearing bush 31. The disc 30 bears two pins such as 34, which are provided with contact switches (not shown) . As soon as the turning of the ship as a whole has become so great that the arm 32 comes to rest against one of the pins 34, the servo motor 29' is put into operation, as a result of which the mast 13 is turned back again by means of the worm 29 and the worm disc 30 until the opening in the mast section is directed downwards. Causing delayed switching off of the servo motor 29' when the guide arm 32 has no further contact with the contact switches in the pins such as 34 makes it possible for the turning back of the mast 13 actually to continue up to the position shown in Fig. 7, in which the mast hollow is in fact directed downwards and the arm 32 is situated approximately in a central position between the two pins 34. The arm 25 bearing the worm and servo motor is shown directed upwards. Since, however, the bush 25' turns along with the bearing column 17 which is firmly connected to the lower ship, the actual direction of the arm 25 will depend on the position which the lower ship assumes in the sea at any moment. Fig. 8 shows a cross-section through the mast 13. The latter has a square box section which is thus open at one side, the side which is intended to be directed downwards all the time. Inside the mast section, an insulator 41 bears a rack bar 43 by means of a supporting beam 42. The insulator serves to provide the possibility of supplying voltage along the rack bar 43 for the drive motor. The vane slide, indicated in its entirety by 36, and which is shown in further details in Fig. 9, is driven along the mast by means of the main gear wheel 44 which is situated in the gearbox 40 for the propulsion of the vane slide on the right in Fig. 9. The drive motor (not shown) is also accommodated here; this motor is designed as a brake motor, i.e. it has brake shoes on its rotor in a manner which is known per se. The main gear wheel 44 projects from the outside through the aperture in the mast 13 and meshes with the rack bar 43 which extends over the entire length in the interior of the mast. The vane slide travels non-rotatably along the mast by means of two rollers such as 46 at the top end and 47 at the bottom end. These wheels 46 have an axial measurement which corresponds to the external measurement of the mast and are on the outside thereof provided with flanges such as 46', 47' (see Fig. 10) which engage on either side around the mast section. While thus the gearbox 40 and the slide piece 48 are non-rotatable relative to the mast, there is between them a tube 49 which is retained between the parts 40 and 48 by means of two conical retaining bearings 50, 51. This tube 49, which is internally larger than the diagonal measurement of the mast, is then therefore rotatable about said mast. It therefore bears in a manner to be described in further detail below the vane feet, one of which is shown in Figs. 9 and 10, indicated by 52. Each vane foot 52 bears a vane shank 53 which is pivotable relative to the vane foot about an axis 54 which lies in a central plane through the axis of the mast. In order to permit swinging of the vane out of the collapsed position which is maintained in Figs. 9 and 10 to the spread position, the vane foot is also pivotable about a shaft 56 which is tangential relative to the axis of the mast. The spreading slide, indicated in its entirety by 37, is shown in further details in Figs. 11 and 12. The construction thereof corresponds to the construction of the vane slide 36 to the extent that there is a rotary central piece between two non- rotatable outside pieces. The bearing roller housing 58 thus, as the name says, bears two bearing rollers such as 59 which in the same way as the bearing rollers 46 and 47 are provided on either side with flanges 59" which engage outside around the mast section. In a corresponding manner the top bearing roller housing 60 bears two bearing rollers such as 61 with flanges which also engage around the mast 13, as can be seen from Fig. 12. Between them there is again a central part in the form of a tube part 62 which is rotatable by means of bearings (in this case not shown in the drawing) relative to the bearing roller housings 58 and 60. A simple solution in design terms is obtained if the parts 58 and 60 are connected to each other by means of an inner tube, so that the bearings for the outer tube 62 can also be fixed relative thereto. This central part 62 can therefore turn with the vanes. For this purpose, it bears a hexagon 65 by means of a bearing ring 63 and three bars such as 64. As will be clear, Fig. 12 is also for the first time a figure in which the three-vane situation is expressly shown. The hexagon 65 is composed of three bearing brackets such as 66 which are connected to each other by simple bars 57, and each of which bears a cross piece 67 to which a spreading bar or tube is fixed; these spreading bars were already indicated by 38 in Fig. 5. In order to permit the spreading, the cross pieces 67 are fitted so that they are rotatable about their longitudinal axis 68 in the bearing brackets 66. Pairs of regulation arms such as 69 are fitted between the cross pieces 67. They serve to ensure that the vanes always have the same degree of spread relative to each other, otherwise an imbalance would occur. For this, each arm 69 at its one end at 69' is pivotable relative to the cross piece 67. The other end is rotatable about the axis in a bush 70 (see the arrows) . Two of said bushes are pivotable at 71 and together form a fork. The top bearing roller housing 60 is extended by a mounting bracket 72 for a hook which has a function in the opening of the slides, shown in greater detail in Fig. 13. Before we go into this, we revert to Fig. 8. In it we see that two further rails 73, 74 are fitted in the interior of the mast 13, next to the parts already discussed. The slide opener 75 can roll along them with the aid of sets of bearing rollers such as 76, 77. The slide opener 75 also carries a toothed rack 78 of the slide opener. In Fig. 13 the slide opener 75 can be seen again, with different pairs of bearing rollers such as 76, 77, and with the toothed rack 78 for the slide opener. A counterhook 79, which can engage behind the hook 80 of the closing coupling, is fitted at the bottom end of the slide opener. Said hook 80 is fitted so that it pivots about a shaft 81 relative to the support 72, and it is retracted to the illustrated position of engagement with the counterhook 79 by the spring 82 which is fixed to an arm 83 which is firmly fixed to the top bearing roller housing 60 of the spreading slide. Disconnection of the hooks 79 and 80 takes place when the uncoupling bar 85, which is fixed to the bottom bearing roller housing 48 of the vane slide, hits the projecting part 84 of hook 80. In order to make the functioning thereof clear, reference is first made to Fig. 9. In this figure, apart from the main gear wheel 44 for the displacement of the vane slide, a gear wheel 86, called a spreading gear wheel, can also be seen. The latter is driven by the same servomotor (not shown) as that which drives the main gear wheel and it is in engagement with the gear rack 78 on the spreading slide 75 (see Figs. 8 and 13). It has a peripheral speed which is approximately 1/4 that of the main gear wheel. When therefore this spreading gear wheel 86 turns - simultaneously with the main gear wheel 44 - while the spreading slide is being moved along the mast, the slide opener 75 will be displaced relative to said spreading slide. As a result of the above-mentioned ratio of the peripheral speeds between the gear wheels 86 and 44, for any distance which the vane slide covers up or down, the slide opener 75 covers one quarter of said distance, but in the opposite direction. At the commencement of the unfolding, when the vanes are still in the hold and thus cannot yet open, provision is made for a free stroke of the bottom part of the slide opener, so long as the latter has not yet reached the spreading slide. The free stroke is formed by the distance which, at the lowest position of the slides in the bottom of the upper ship, exists between the bottom part of the gearbox 40, where the bottom end of gear rack 78 is approximately then situated, and the top end of the spreading slide 37 against which the gear rack finally has to press in order to achieve the vane spread. In the case of the relationships of the parts shown in the drawing it can be seen that this free stroke must be 1/4 of the travel which the slides have to make from the starting point to the point at which the vanes can unfold freely. That is approximately the height of the flange edge 27. Until that point is reached the vanes are still confined in the ship and cannot yet unfold. However, as soon as that free stroke is completed, the slide opener 75 begins to push against the coupling hook 80, and thus against the spreading slide 36, as a result of which said spreading slide moves away from the vane slide and the spreading of the vanes begins. With the further rising of the vanes along the mast this vane spreading continues proportionately, until the vanes finally reach their highest point on the mast, corresponding to a position of the vanes which is completely at right angles relative to the mast and a maximum mutual distance of the slides, as shown in Figs. 4 and 5. In order to permit closure of the vanes during their lowering, vane slide 36 and spreading slide 37 must, of course, move towards each other. The coupling shown in Fig. 13, called a closure coupling, at the top end of the spreading slide, is used for this. As soon as the vane slide 36 starts to drop and the slide opener 75 going in the opposite direction is about to move up, i.e. to move away from the spreading slide which it pressed upwards during the rise of the vanes, the coupling hook '80 slots into the hook 79 of the spreading slide, as shown. As a result, the spreading slide 37 is carried along by the slide opener 75 - which can now better be called slide closer - to the vane slide 36, and the vanes fold up. As soon as on further dropping of the vanes the vane slide and the spreading slide are very close to each other, the bar 85 situated at the bottom of the vane slide ensures that the closing coupling, which has now completed its closing work, is pushed free again. This means that on further dropping of the slides the slide opener 75 moving further up will begin its earlier mentioned free stroke, this time in the opposite direction, thus returning to its starting point. The point of the mast on which this takes place is approximately at the level of bottom and top deck. The vanes are then completely folded up, so that on further lowering they fit into the ship's hold. Of course, this vane return described here can also take place at any other height on the mast and at any other spreading level of the vanes. Moreover, it need not always mean a complete withdrawal of the vanes into the ship's hold, but can be only a partial reduction in height, if it is taking place on account of too strong a wind, in which case the vane rotor shifts only a part of the excessive wind supply. The servomotor for displacement of the slides has only one direction of rotation, namely only for moving the slides upwards. The slides roll downwards by themselves, through their own weight and fully automatically. The vane return described occurs not only on the command of the control equipment, but also in the case of any conceivable fault, thus also if, for example, the rotating ship were to be left entirely to its own devices. It is thus a completely automatically operating inbuilt safety device. This automatic creeping of the vane rotor into its shell cannot degenerate into a free fall, because the servomotor which has become de-energized remains coupled to the vane slide, and thus has to turn back. This "controlled" turning back, which slows down the speed of lowering, can be slowed further by connecting the voltage which the servomotor generates during turning back to electrical resistors. As already said, the vane cross-sections (chords) of a power ship rotor, through the slanting position of the ship in the sea, do not have the correct inflow angle relative to the wind in the horizontal phase of their revolution. In order to correct this, the vanes are not fitted directly on the rotary part of the vane slide, but a vane position corrector is present. The design thereof can be seen partially from Figures 9 and 10, and it is important here to point out that those vanes, at least the bottom parts 52, 53 thereof, are shown in the lowered position. For the design of the vane position corrector there is further referred to Figures 14 and 15, but they show the device in operation, thus with spread vanes. The vanes rest on a separate bearing disc, called a correction disc 87. This disc is fixed to the outermost unit 88 of two Cardan rings 88, 89, the innermost one of which is connected to the rotary central part 49 of the vane slide. Through the accommodating action of these Cardan rings, the correction disc is not forced to remain rotating in only one plane at right angles to the axis of the rotary ship. If lateral pressure is exerted on it, it can deviate from that normal direction of rotation and rotate, for example, in a plane deviating 35' therefrom, thus at right angles to the wind direction. The lateral pressure necessary for that is supplied by a pressure ring 90 which is provided with four bearing rollers 91. This pressure ring 90 is hingedly connected at 92 to the fixed, thus non- rotating, part 48 of the vane slide and is pulled up to 35' to the side by a strong spring 93. The correction disc 87 is thereby rolled in a plane at right angles to the wind direction and the vane cross-sections of the vanes mounted thereon, of course, also move in that right-angled plane relative to the wind. This means that once an inflow angle has been given to the vanes it is kept constant. In order to enable the vane position corrector to push the correction disc always in a perpendicular plane, the mast on which it is fitted must always be directed with the same side downwards in all positions of the ship. It is for that reason that the mast is rotatable and is provided with the mast guide mechanism, as described. This above-described correcting action of the correction disc on the cross-sections of the vanes takes place only if the lengthwise direction of the vanes does not deviate too much from a right-angled position relative to the mast. The more the vanes are folded along the mast, and the more they thus come to lie at right angles to the correction disc, the less they obey its spring pressure, until the vanes in the end lie entirely along the mast and then react no further at all to the pressure rollers. In that position of the vanes along the mast there is, however, no further need for a correction of the vane position. For, power ship and vanes are then at rest, and the fact that the correction disc, which is then pressed at right angles to the mast by the no longer displaceable shanks of the folded-up vanes, no longer functions is then actually better for the storage of the vanes. For, it means a uniform position of the vanes relative to the ship's bottom. Of course, the vane position correction discussed here relates only to keeping the vanes constant in a once selected pitch angle of their chord, thus their crosswise direction. In their lengthwise direction the vanes are, of course, not corrected by it and, if they are standing at, for example, right angles to the mast, they continue to describe a plane of 55' relative to the wind direction. Fig. 16 gives a side view and Fig. 17 a front view of the vane and the spreading tube, shown in the folded-up position. The vane foot 52 and the vane shank 53 from Figs. 9 and 10 can be seen. Between them a flexible connecting piece 45 is inserted. The spreading tube 38 from Figs. 11 and 12 can be seen, with the cross piece 67 which is rotatable about the axis 68. An auxiliary spring 45, which with its other end, at 95, is fixed to the centre of bar 65 (cf. Fig. 12) is fitted on the spreading tube 38. This auxiliary spring is used to close vanes and slides quickly. The end of the spreading tube 38 is fixed pivotally to the vane hinge 97 at 96. The vane hinge 97 is formed by a bar which is fixed by two brackets such as 97' to the vane 14, in such a way that said bar 97 is rotatable about its axis, with a view to the pitch angle adjustment of 53 not discussed in any further detail here. Figs. 18 and 19 show in front and side view respectively a detail of the coupling between the rotating vanes and the power ship. Fig. 19 shows the bearing bracket 98 which (cf. Figs. 11 and 12) is welded to the bearing brackets 66 of the hexagon of the spreading slide. A connecting piece 99 is fixed thereto in such a way that it is pivotable about a shaft 100. The connecting piece 99 bears pivotally two parallel adjustable bars or tubes 101, 102, the other ends of which are pivotable relative to a connecting piece 103. The diagonal screw spindle 104 fixed between the parallel bars 101, 102 is used to set the correct position of the parallelogram formed by said parallel bars and the connecting pieces 99, 103. The screw spindle is made left-handed at one side and right-handed at the other side in order to permit setting of the effective length between the screw bushes 105, 106 fixed to the bars. The connecting piece 103 is made bracket-shaped and bears a guide roller 107, of the type with a semi-circular section, indicated by 107', ending in upright flanges 107". This roller 107 runs on the inside along one of the parts 9' of the bars or tubes forming the cage. In the process it stands under the pressure of the spring 108, which is fixed at one side to the projecting arm 109 of the connecting piece 99 and at the other to the arm 110 of the bracket 98. The parallel adjustment of this coupling, thus in the peripheral direction, with the aid of the screw spindle 104, serves to determine the correct position of the vanes between the bars or tubes 9 between which they project outwards. In the case of broad vanes in particular this position responds precisely. The force of the springs such as 108 must be sufficient to ensure that the guide rollers such as 107 carry along the cage 8 with the rotation of the vanes 14. As can be seen from Fig. 17, the vane shank 53 is fixed rotatably outside the centre of the vane chord. Since as a result one half of the blade catches more wind than the other, the vane will be able to fold away in strong gusts of wind. The spring 111 returns it to its place. This possibility is for short called the self-yielding of the vanes. Figs. 20 to 22 show a design for a possible pitch angle adjustment. A windmill delivers its greatest power in any wind only at a certain speed of rotation and a certain pitch angle of the vanes. The speed of rotation can, as already said, be adjusted constantly by switching generators on or off. The need for an adjustment facility of the pitch angle can be less in smaller power ships if the vanes are provided with so-called tip vanes. For the latter result in a more profitable working of the rotor with changing wind force even without pitch adjustment. In the case of larger power ships, in particular at higher running speed, which requires a more accurate pitch angle, the need for a pitch angle adjustment becomes greater. Figs. 20 to 22 give a variant of the design of the vane rotor for this. The disc 87 of the vane position corrector, the vane foot 52 which is pivotable about the axis 56, and the vane shank 53 can be seen here. The axes of rotation or vane foot shafts 56 are now provided at both ends with crown wheels such as 116. By means of added connecting shafts 117, which are also provided at both ends with crown wheels such as 118 which are in engagement with the crown wheels such as 116, the vane foot shafts are connected to each other, to form a closed hexagonal shaft system. This thus produces a shaft hexagon lying in a radial plane through the axis of the mast, which will be indicated below in its entirety by 119, and which is formed by three vane foot shafts such as 56 and three connecting shafts such as 117, coupled together by the crown wheels such as 116 and 118; when one of the shafts thereof is rotated, all shafts receive the same direction of rotation and angle of rotation. The vane foot shafts 56 each carry in their centre a worm 120 which is confined in a recess 121 in vane foot 52. The vane shanks 53 situated above these worms were placed, without pitch adjustment, directly with their flexible connecting piece 94 on the vane foot (see Fig. 16) . In the present modification they are placed on a worm wheel shaft 122. The latter is rotatably mounted in a bearing bush 123 which is built on against the vane foot 52, and through which it projects and at the end bears a worm wheel 124 which is in engagement with the worm 120. The vane shank 53 is fixed on the worm wheel shaft 122 by means of a T-shaped cross piece 125 on said worm wheel shaft and a U-shaped connecting piece 126 on the bottom end of the vane shank 53, with a hinge pin 127. A flexible layer between the parts 125 and 126, for a supple vane arrangement, is in turn indicated by 128. This connection is in itself pivotable with a view to the above-mentioned self-yielding of the vanes. The shafts 56 and 117 are rotatable in bearing supports such as 129. Fig. 20 shows at 130 a servomotor for driving the shaft hexagon 119. This motor is called a pitch adjustment motor. Such a motor will, of course, act with a great deceleration on the one connecting shaft 117 at which it is fitted. It can turn all shafts of that hexagon simultaneously, and by means of the worm transmissions 120, 124 the pitch angle of the vanes can thus be altered. The device works as follows. The first rule is that the speed of rotation of the turbine is constantly adapted to the constantly changing power supply in the form of the wind which continuously changes in forces. The criterion here is to obtain the optimum performance. The first means proposed according to the invention is to switch on and switch off as many generators as possible to meet this criterion (in addition, all measures are, of course, actually applicable to the item of construction, shaping and adjustment of the pitch angle of the individual vanes insofar as it is felt that these are needed in a specific case, but these measures do not form any part of the present invention) . The end of the first regulating stage is reached when all generators present are switched on. If the wind increases further and the risk limit, which is based on the strength with which the vanes are designed, is being approached, the vane rotor is pushed downwards, while through a lower axial shift of the unfolding slide the unfolding bars ensure that the vines come to lie at an angle less than 90" relative to the shaft direction, thus the vane rotor is made concentrically smaller. In this way the cross-section of the flow tube of the vane rotor is reduced. This achieves a relative reduction of the power taken up from the wind by the rotor, but because in fact the power supplied is greater through the greater wind speed the power taken up by the generators could remain roughly the same. Insofar as in a specific dimensioning case the power taken up decreases in that position, generators can be switched off if necessary. The reduction of the flow tube cross-section can continue to, for example, the position of Fig. 3. The third regulating stage commences when the wind force increases even further and in the last- mentioned position too great forces also threaten to occur on the vane rotor. The vane rotor can now be reduced further and be partially slid into the ship, as shown in Fig. 2. Only a relatively small part of the wind supply is now being used, in which case, as in the previous stage, further generators can be switched off if necessary, but the turbine continues to work to take up as much wind power as is still reasonable in view of wind pressure still occurring or the forces on the vane rotor. The fourth regulating stage is reached when the storm is too risky even for only partially projecting vanes, as seen in Fig. 3 or Fig. 2, and they are then taken into a fully collapsed position as shown in Fig. 1. There is nothing against them then still projecting along one fifth of their length beyond the protection of the hold of the ship 6, because in that case forces of fatal value can never occur. This part of the length can thus be saved on the axial length of the hull of the ship 6. The turbine can also continue to rotate in this position, with a suitable number of switched-on generators. Because in increased length of the slip would result in an increased stability in the water, it would also be feasible to choose this length such that the vanes, in their retracted position, don't project beyond the hold, so that the hold can even be closed at the top. It is by no means always so that the angle of the vane rotor shown in Fig. 5in normal working weather is the position which gives the highest performance when wind energy is being taken up. In this position the vanes are in fact always at an angle of 25 to 30' (the complement of the selected angle α relative to the wind direction) . For each vane assessed separately there is thus a question of an oblique flow of the wind, which is a disadvantage as a rule. If the rotor is given the position relative to the axis which is shown in Fig. 5, in which the vanes lie not at 90', but at approximately 60', relative to the shaft direction - which would thus amount to the rotor with the position of Fig. 5 being displaced relative to the shaft up to the end of said shaft through displacement of the two slides along equal distances - a straight flow to the vanes which are situated in the highest position is obtained, which is beneficial for the force exerted at that moment on said vane or the wind power to be transferred to it. The consequence is, however, that the vane which is in its lowest position has to suffer from an even more oblique flow, so that the pressure there clearly falls. In all positions of a revolution of a rotor lying in between one has, of course, to contend with an intermediate situation. Assuming that the wind force at a height of 100 m is 20% stronger than at 10 above the sea and the available power at that place (always increasing by the power of three of the wind speed) is thus almost 75% higher, the earlier mentioned advantageous factor will soon dominate, to such a great extent that there is compensation for the in itself adverse effect of the reduction of the flow tube in that rotor position, by comparison with the perpendicular position according to Fig. 5. All this is, however, dependent on the dimensioning in each specific case, and it will therefore have to be established for each design what in the end is the optimum position of the vane rotor relative to the shaft in normal working weather. The following can be pointed out with regard to the angle α of the shaft relative to the horizontal. In general, it can be said that the proposals according to the invention as regards making the vanes of the vane rotors pivotable and slidable relative to the shaft are applicable to a turbine which is fitted with horizontal shaft direction on a mast or tower. However, precisely because these proposals lay the basis for making plants of large dimensions, in particular with large vane dimensions, placing on a tower or mast is a disadvantage because that mast in turn is exposed to much greater stresses than the known turbines placed on a mast. Placing in the proposed slanting position with fixed anchoring relative to the ground eliminates the problem of great moments on a mast. If the same idea is carried out on land, one is again limited, inter alia because a round piece of ground which is determined by the points of the vanes in their lowest position would then have to be kept free, with provisions for drifting around of the whole unit through this whole circle. It is precisely at sea that the space problem is not important, however great the dimensions are made, while it is clear that through making use of the floating capacity of a ship the whole problem of the support in the form of a drifting device does not exist. The disadvantage existing in the first instance of placing of a turbine at an angle instead of with the shaft parallel to the ground is that the flow of the wind to the vanes is oblique, thus less beneficial, while the cross-section of the flow tube also becomes elliptical, thus is reduced. However, with the slanting position proposed by the invention the possibility is immediately obtained of selecting the dimensions at a multiple of those which can be used with horizontal placing of the turbine, necessarily on a mast. This is already a satisfactory enough effect of a slanting position, which effect, as already said, becomes much greater with the design as a ship. In order to be more specific, it can be stated that the loss of power from a slanting position by- comparison with a horizontal position, thus with right-angled placing in the wind on the basis of a model, came to 11% at α = 25', and 16% at α = 30'. In view of the fact that in aerodynamics second-degree and third-degree dependences prevail, experimental research on the basis of a reduced model cannot be made absolute. Nevertheless, the above-mentioned values give some idea of the effect of the slanting position relative to the theoretically optimum horizontal position. It is known that auxiliary vanes fitted at the vane tips (tip vanes) have the capacity of shifting for each vane the turbulence generated by the rotating predecessor partially outside the flow tube. A zigzag eddy which builds up a sort of eddy wall is produced. This increases the original flow tube of the vane rotor, and it thus also increases the capacity. This greater flow tube also still remains in position when the vane rotor is rotated to 25' out of the wind, as is proposed according to the invention. It can thus be said that through the fitting of tip vanes there is partial compensation for the loss of power of the slanting position relative to the horizontal position. The increase in power through the use of tip vanes is known. In any case it seems justified for the slanting turbine according to the invention to use the generally applying capacity formula of wind turbines: P = 0.00044 . D 2 . V s kW, in which D is the diameter of the vane rotor and V is the wind speed. In view of the fact that the power depends quadratically on the dimension, it is now also clear that a theoretical loss of power through a slanting position instead of a horizontal position (11 to 16%) is already compensated for by an increase in scale of 8%. In the case of turbines according to the invention the so-called smoothening limit - above which power is taken up but with the excess being smoothened by e.g. pitch adjustment etc. - can be set much higher than in the case of turbines on land. Land turbines generally have to be smoothened off already when the wind increases to above 13 m/sec. According to the invention it is recommended that this stop limit should be set at 18 m/sec. In itself an even higher limit would actually be feasible, but winds of 20 m/sec and stronger occur less than 5 hours per year in the Netherlands. On the contrary, they are so gusty - with the quadratic effect thereof in respect of the wind pressure - that absorbing those sudden changes in speed would call for expensive technical facilities. Since the number of hours of occurrence of these wind speeds is less than 3% of the annual yield, and an increase in cost to permit working with them would be much higher than 3%, the facilities are not worthwhile, and exceeding the limit of approximately 18 m/sec is not beneficial. A good compromise between the costs (of the technical facilities) and the benefits (in the form of current yield) would seem to be to take the maximum capacity of the power ship at 18 m/sec and to level off a higher power uptake than that going with this speed value by partially retracting the vanes as described, until the power going with 18 m/sec is obtained. These figures, which are based on currently known information concerning the cost, do not, of course, constitute any limit on the inventive idea as such; the power ships according to the invention can also work by itself if the retracting of the vanes does not start until there are wind speeds which are higher than the value of 18 m/sec. In all cases the smoothening limit can be set considerably higher than with turbines on land. An increase in the stop limit from 13 to 18 m/sec thus means a greater power uptake of 18' : 13', i.e. 2.7 : 1, although this ratio is reduced slightly through the fact that such winds up to 18 m/sec occur less frequently. In view of the relatively great increase in any case of the energy abundance brought in when there is stronger wind, it is of the utmost importance to set the smoothening limit as high as possible. The invention provides a series of significant means for this. First of all, there is the possibility of holding the speed of revolution in check by switching on generators. Then there is the possibility of reducing the vane rotor steplessly and storing it. In the third placβ-, there is the self-yielding nature of the vane rotor which is described in connection with the dimensioning of the braking on the rotor slide and the unfolding slide. Finally also, in a more general sense, there is the strength of the vane construction, because neither the dimensions nor the weight of the vanes constitute limiting factors in the design of a turbine according to the invention.

Claims: CLAIMS 1. Device for harnessing wind energy, comprising a number of propeller elements which are fitted rotatably on a rotary shaft which is coupled or can be coupled to an electricity generator situated in the housing, the housing being pivotable about a vertical axis, characterized in that the propeller elements (14) are pivotable about tangential axes relative to a slide (36) which is slidable along the shaft (13) , and that they are provided with means (37, 38) for holding them in an angular position relative to the shaft and for altering that angular position. 2. Device according to Claim 1, characterized in that the means for holding and altering the angular position of the propeller elements (14) comprise bars (38) , one end of which is hingedly fixed on an intermediate point along the length of the propeller elements, and the other end of which is hingedly fixed to a second slide (37) which is slidable along the shaft. 3. Device according to Claim 2, characterized in that the means for holding and altering the angular position of the propeller elements further comprise motors which determine the position of the two slides (36, 37) relative to the shaft. 4. Device according to Claim 3, characterized in that at least one of the two slides (36, 37) is also provided with a brake by means of which they can be fixed in any position relative to the shaft. 5. Device according to Claim 4, characterized in that a drive motor (40) for altering the angular position of the propeller elements is designed as a brake motor. 6. Device according to any of Claims 1 - 5, characterized in that the propeller elements (14) in their fully collapsed position, in which they form a minimal angle with the shaft, are situated at least with the greater part of their length in a chamber in the housing (2) . 7. Device according to any of Claims 1 - 6, characterized in that the slides (36, 37) are displaceable relative to the shaft (13) with the aid of at least one gear wheel (44) which is fitted on the slides and interacts with a rack bar (43) fitted on the shaft. 8. Device according to any of Claims 1 - 7, characterized in that the axis (3) of the shaft (13) or of the housing (2) forms an angle with the horizontal. 9. Device according to Claim 8, characterized in that the angle is around 35'. 10. Device according to any of Claims 1 - 9, characterized in that the propeller elements (14) together with a cage (8) comprising at least three bars (9) are rotatable relative to the housing (2) , while the shaft (13) is essentially stationary relative to the housing (2) . 11. Device according to Claim 10, characterized in that a cog wheel (21) is connected to the cage (8) , along which cog wheel several generators (23) which can be brought into engagement separately with the cog wheel are disposed. 12. Device according to any of Claims 1 - 10, characterized in that the housing (2) is designed as a ship which is disposed so that it pivots relative to the seabed. 13. Device according to any of the preceding claims, characterized in that the two slides (36; 37) are composed of a central part (49; 62) which is rotatably accommodated between a top part (40; 60) and a bottom part (48? 58), the latter parts being provided with bearing rollers (46, 47; 59, 61) which are displaceable along the mast (13) . 14. Device according to any of the preceding claims, characterized in that the propeller elements (14) have, relative to the slide (36) by which they are carried, a Cardan attachment (88, 89), in that one (88) of the Cardan rings thereof is connected to a pressure disc (87) , and in that a pressure ring (90) is connected to one (48) of the non-rotatable parts of the slide (36) so that it pivots about a tangential axis (92) , said pressure ring bearing pressure rollers (91) which are pressed against the pressure disc (87) by a spring (93) which is fixed between the pressure ring (90) and the above- mentioned part (48) of the slide, in order to keep the pressure ring in an angular position relative to the shaft (13) . 15. Device according to any of the preceding claims, characterized in that the middle rotatable part (60) of the spreading slide bears cross pieces (67) which are fixed to the spreading bars (38) and are pivotable about tangential axes (68) relative to bearing brackets (66) which are interconnected to a hexagon (65) . 16. Device according to Claim 15, characterized in that the cross pieces (67) are connected by pairs of regulation arms (69) which are rotatable about their axes in mutually pivoting bushes (70) , and which make the individual spreading movements equal. 17. Device according to any of the preceding claims characterized in that a slide opener (75) is present between the vane slide (36) and the spreading slide (37) , said opener being displaceable relative to rails (73, 74) , which are fixed to the mast, by- means of a toothed rack (78) and a gear wheel (86) which meshes therewith and is driven by the motor which serves for the displacement of the vane slide (36) along the mast, but at a so much lower peripheral speed that with each displacement of vane slide (36) in one direction along the mast a displacement of the slide opener (75) takes place over a fraction of said displacement distance in the opposite direction. 18. Device according to Claim 17, characterized in that the above-mentioned fraction is one quarter. 19. Device according to Claim 17 or 18, characterized in that the slide opener in the fully collapsed position of the vanes has a free stroke before it starts to press against the vane slide (36) , which free stroke is 1/4 of the distance which the vanes have to cover in the upper ship before they can unfold. 20. Device according to any of Claims 17 - 19, characterized in that the spreading slide (37) and the slide opener (75) are each provided with a hook (80, 79) which can go into engagement with each other as a closing coupling, in order thereby to carry along the spreading slide (37) with the vane slide (36) and the slide opener and make the vanes fold up. 21. Device according to Claim 20, characterized in that the vane slide is provided with a pin (85) which in its lowest position takes the hook (80) fixed to the spreading slide out of engagement with the hook (79) on the slide opener. 22. Device according to any of the preceding claims, characterized in that the spreading slide (37) presses with rollers (107) by means of parallel bar structures (101, 102) which are under spring action (108) against and is displaceable relative to the supporting tubes (9, 9') of the cage structure (8) . 23. Device according to any of the preceding claims, characterized in that the pitch angle of the vanes (14) is adjustable relative to the vane slide (36) , through the fact that the shafts (56) of the vane feet (52) are provided with worms (120) with which worm wheels which are fixed to worm shafts (122) bearing the vane shanks (53) are in engagement, while the above-mentioned vane foot shafts (56) are interconnected by means of crown wheels (116, 118) and connecting shafts (117) provided with crown wheels, in order to produce an equal pitch adjustment of all vanes from a single pitch adjustment motor (130) .

Inventors: BAKKER JOHANNES PETRUS, BAKKER, JOHANNES, PETRUS
Applicants: BAKKER JOHANNES P, BAKKER, JOHANNES, PETRUS
Application year: 1990
Main classification: F03D7
IPC codes: F03D1