NZ239140A - Vertical axis windmill with paired feathering and - Google Patents

Description

23 9 1 4 CoSp<3v^it teuton T"«<cfdi Fo3^S,Wfo FEB 1994 Publication Date: P.O. JriL-n-.', Iv: ,. r5>XK s£'~"\ »• •'*• i :''x .<* \ v. ;;v "A 'i ti f,:j 2 6JULl99ii bsivlV NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION "Improvements in or Relating to Wind Energy Collection Apparatus"" WE, URS RINGER and BENO RINGER, both Swiss Nationals of Otv^Wr . respectively/PO-Box 203,' Mangonui^ Northland'and Nordstrasse 80 8006 Zurich, Switzerland DO HEREBY DECLARE this invention to be described in the following statement: 23 9 1 4 0 The present invention relates to improvements in and relating to wind energy apparatus.

Wind is one of the oldest energy sources used by mankind. The Persians were probably the first to use kinetic energy from wind with the help of windmills as early as the seventh century. Their windmills pumped and delivered water for irrigation purposes. Around 1900 there were approximately 100000 windmills at the North Sea coast, between Holland and Denmark. They pumped water, ground corn, operated sawmills, oil presses, paper mills, crush mills and others. Windmills were used in Denmark as early as 1890 to generate power. After the Second World War research work was neglected in favour of more cost-effective technologies. Only the energy crisis of 1973/74 saw a renewed interest in wind energy, renewable energy sources such as wind become more and more important because of the ecological problems and limited fossil fuel resources, as well as the growing concern about nuclear energy.

The use of wind energy is determined by locating, meteorology and the technology required to transform the kinetic energy of the wind into useful rotating motion. At present, there aie two concepts of wind energy used. Horizontal axis rotors are the most common ones applied.

These rotors have to be placed in the right position relative to the wind. This is done by turning the tower head where the rotor is fitted. In small installation this can be accomplished by means of a wind vane behind the rotor, or a second small rotor parallel to the wind direction. In big power stations the alignment of the rotor is achieved by a complicated series of large-scale control devices. We distinguish two types of horizontal axis rotors: Multi-vane rotors and two and three-vane rotors. Multi-vane rotors are fitted with 12 to 24 rigid mounted rotor vanes. This system can 239140 start at very low wind speeds because of the large wind catching area of the many vanes.

The rotor vanes of the two and three-vane rotors can be turned around their longitudinal axis. This enables to keep a constant rotor speed during changing wind speeds. Constant speed is necessary for the generation of electrical alternating current Apart from the horizontal axis rotors, there are special types with vertical axis rotors in operation or development They are made by "Darrieus Rotors" and/or by "Savonius Rotors", they have the advantage of not having to be aligned into the wind. Darrieus Rotors have the disadvantage of not being able to start by themselves, they have to be combined with Savonius Rotors or motors.

The invention sets itself the task of making a rotor for a wind power plant, highly efficient and designed so it does not have to be aligned with the wind and also capable of operating in light winds.

In a first aspect the invention consists in a wind energy collection apparatus of a kind having a substantially vertical axis about which an even number of vanes can rotate in a wind to provide a power output; wherein each vane comprises a plurality of flaps each arranged to swivel or rotate substantially transversely of said substantially vertical axis and said flaps are paired by attachment to a means of exclusionary relationship such that when one flap of a pair is in a substantially non-feathered condition the other is necessarily in its substantially fully feathered condition.

Preferably said flaps each swivel or rotate about a substantially horizontal axis defining means, the swivelling rotation being at an upper region or edge of the flaps.

(A.C.). ' ■ 2391 Preferably said means of exclusionary relationship consists of an axial member to which the flaps are rigidly attached, said axial member being free to rotate transversely.

Preferably a stop prevents a downwind moving flap from moving substantially through a vertical plane through the said substantially vertical axis.

Preferably the said paired flaps are arranged about said axle member at substantially 90° to each other.

Preferably the power output is mechanical or electrical.

Preferably each vane is of staggered flaps.

The preferred forms will now be described.

The new rotor is a vertical axis rotor. Two or more rectangular rotor vanes or vanes 2, fitted radially to the outside, substantially vertically arranged, are fitted to the central vertical axis of rotation. The rectangular vane surfaces are subdivided into several surfaces (flaps, lamellas, elements) arranged one on top of the other and individually swivelling insofar as a single vane is concerned.

Figure la is a three dimensional diagram of a four vane rotor.

Figure lb is a plan of the rotor shown in Figure la.

Figure 2a is a side view of a four vane rotor.

Figure 2b is a top view of a four vane rotor. All flaps are open.

Figure 3a is a cross-section of a flap about to be closed by the arrow designated wind force as it commences downwind movement.

Figure 3b is a cross-section of the closed flap of Figure 3a.

Figure 3c is a cross section of the flap of Figures 3a and 3b being opened by the wind force as it commences upwind movement Figure 3d is a cross-section of a fully opened (feathered) flap of Figure 3c into the wind.

Figure 4a is a top view of a two vane rotor.

Figure 4b is a top view of a four vane rotor.

Figure 4c is a top view of a six vane rotor, and Figure 5 shows how, with paired vanes, the flaps thereof can be paired such that the downwind flap always provides at least some of the rotational force needed to feather the upwind flap.

As mentioned before, the surface of the rotor vanes 2 is of rectangular shape. The surface of each vane 2 is divided into several flaps 3, situated one on top of the other, with a slight overlap of the lower flap by the one on top (see Figure 1, Figure 2 and Figure 3b). The upper edge of each flap is fastened to a horizontal swivelling axis that runs across the surface of the rotor vane. The flaps 3 can be swung into the horizontal line from one side of the rotor vane surface (see Figure 3c). A swivel to the other side of the surface is impossible because the flaps 2 touch the swivelling axis 4 of the flap 3 situated below and thus are blocked into the vertical position (see Figure 3b).

A cross bar 5 at the lower flap, into which the flap touches in the vertical position, prevents swivelling beyond the vertical line onto the other side of the vane surface. Viewing the rotor vanes 2 from the central axis of rotation 1, either all flaps 3 of a rotor can swivel to the left or all flaps 3 can swivel to the right into the horizontal line.

The rotor vanes 2 are mounted at the central vertical axis of rotation 1, so that two vanes 2 face each other and are both in one plane. The vanes facing each other are equipped with a horizontal axle 4 from which a flap from each pair of vanes is attached. The flaps 3 are preferably rigidly fitted to a common swivelling axle 4 so that their surfaces stand substantially at right angles to each other (see Figure 5).

The function of rotors is shown with the example of a four vane rotor. Figure la shows a three dimensional diagram of a four vane rotor. Here all flaps 3 as viewed from the central axis of rotation 1 can be swivelled out of the rotor vane surface.

The direction of the in-flowing wind is indicated with an arrow. Diagram lb shows the ground-plan of the rotor la. The wind direction is marked with an arrow which defines a windstream line 7 which in turn passes in the direction of the wind through the central axis of rotation 1 of the rotor. The flaps 3 of the rotor vanes C and D, as viewed from the direction of the wind to the right of the windstream line 7 are closed by the inflowing wind. The wind power affecting the closed flaps 3 creates •p "CE1 ^ a torque force that tends to move the rotor into an anti-clockwise sense. The flaps 3 of the rotor vanes A and B, let in the windstream 7, are opened by the inflowing wind negating operating surfaces to the inflowing wind and thus no torque effect is created. The rotor is set into an anti-clockwise rotation motion around the central axis 1. The flaps 3 of rotor vane 2, viewed from the wind direction, which crosses the windstream line from right to left, will be opened by the inflowing wind (see Figure 3c) and remain in the open position (see Figure 3d) until the rotor vane 2 passes the windstream line 7 from left to right After passing, the wind blows into the other side of the flaps 3 and makes them close (see Figure 3A and 3b).

The movements of flaps 3 facing each other are synchronized. The opening of flap 3 has to result in the closing of the opposite flap 3 against a stop or other abutment. This causes the flap movements to be fast and precise, which in turn results in a better utilization of the wind, the reason being, the faster a flap 3 passing the windstream line 7 from left to right closes, the faster the wind will have the whole flap surface as a working area. The faster a flap 3 passing the windstream line from right to left opens, the smaller (lower) the slowing-down effect of the wind will be.

Rotors whose lamellas open up to the left, as viewed from the central axis, rotate clockwise.

A rotor can be equipped with two, four, six or more rotor vanes 3 (see Figure 4a to c). The number will be adjusted according the prevailing winds at a time.

The rotation energy of the rotor can be used for different purposes. It can drive mechanical machines (pumps, mills, etc.) or power generators.

The new rotor has a number of advantages.

Because of the vertical rotation axis 1 and the refined mechanics of the flap, the position of the rotor does not need a constant alignment with the wind dire&tjo/i. 0 A- y<t, ^' -7- .j < *-4M)Gt993 \ O The rotor can thus be installed rigidly. In contrast to the Darrieus Rotor, the new flap vane rotor also works in weak winds, the rotor vane with closed flaps offers a very large working area to the wind, compared to the working surface of two or three vane rotors. A high degree of efficiency can therefore be expected. The new flap vane rotor is suitable to operate in areas of low wind speeds. ' - 4 AUG 1993 2391

Claims (9)

WHAT WE CLAIM IS:

1. A wind energy collection apparatus of a kind having a substantially vertical axis about which an even number of vanes can rotate in a wind to provide a power output; wherein each vane comprises a plurality of flaps each arranged to swivel or rotate substantially transversely of said substantially vertical axis and said flaps are paired by attachment to a means of exclusionary relationship such that when one flap of a pair is in a substantially non-feathered condition the other is necessarily in its substantially fully feathered condition.

2. Apparatus of claim 1 wherein said flaps each swivel or rotate about a substantially horizontal axis defining means, the swivelling rotation being at an upper region or edge of the flaps.

3. Apparatus of claim 1 or 2 wherein said means of exclusionary relationship consists of an axial member to which the flaps are rigidly attached, said axial member being free to rotate transversely.

4. Apparatus of claim 1, 2 or 3 wherein a stop prevents a downwind moving flap from moving substantially through a vertical plane through the said substantially vertical axis.

5. Apparatus of any one of the preceding claims wherein the said paired flaps are arranged about said axle member at substantially 90° to each other. <l J 4/1 4 0

6. Apparatus of any one of the preceding claims wherein the power output is mechanical or electrical.

7. Apparatus of claim 1 or 2 wherein each vane is of staggered flaps.

8. Apparatus substantially as hereinbefore described with reference to any one, some or all of the accompanying drawings.

9. A method of collecting wind energy using apparatus of any of the preceding claims.p,T.g/(^ DAY C-F Oece,wvb^/ \Q&b -10-