CA2569386A1

CA2569386A1 - Windmill

Info

Publication number: CA2569386A1
Application number: CA002569386A
Authority: CA
Inventors: Frederick Churchill
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-11-30
Filing date: 2006-11-30
Publication date: 2008-05-30

Description

WINDMILL
FIELD OF THE INVENTION

The present invention relates to an apparatus for generating power from the wind.
BACKGROUND OF THE INVENTION

Wind is one of the oldest sources of energy. Although its use is many centuries old, it has not been a dominant factor in the energy picture of developed countries because of the abundance of fossil fuels. However, the realization that fossil fuels are in limited supply and the environmental consequence of burning fossil fuels has awakened the need to develop wind power utilizing modern technology. Indeed, many governments are legislating that a certairi percentage of energy use must be generated by renewable resources such as solar and wind power. The essential ingredient in a wind energy conversion system is the wind turbine which has traditionally been called a windmill. Today, many different configurations of windmills have been proposed, each having its own strengths and weaknesses. One of the major determining factors is the wind speed which is available.

The amount of energy available in the wind is proportional to the cube of the wind speed.
Typically, wind speeds greater than 3 meters per second are needed before wind energy systems can begin to generate electricity. There is also a "cut-out" speed, which is usually around 20 meters per second, where the turbine stops to protect itself from damage. The precise amount of energy that can be extracted from the wind is complicated and depends on such factors as the variability and distribution of wind speed, height of the rotor, diameter of the area swept by the rotor, density of the air, etc.

The experience with most commercial wind farms is that the amount of energy - I -produced is substantially less than what has been calculated. One of the reasons for this is the fact that in most localities, the wind speed is too low to efficiently produce power. This has led to so-called wind farms which are usually located in remote districts where the wind blows at a higher than normal velocity.

There are a nuniber of different vertical wind turbine designs. These range from those turbines having two or three blades having a constant blade pitch angle, though they do have a pitch change mechanism which can be used to feather the blades in extreme wind conditions. Also known are cross wind axis turbines which have the advantage of the elimination of the requirement to drive the axis of the turbine into the wind.
Among known cross wind axis turbines are the Savonius rotor which is comprised of semi-cylindrical offset cups rotating about a vertical axis. A second type of cross wind axis turbines is the Darrieus rotor which incorporates high performance symetric air foils formed into a curve called a troposkien. This shape is selected to minimize the bending stresses in the blades.

The cyclogiro wind turbine is also known. In this turbine, the air foils are straight and the orientation or pitch of the blades is continuously changed during the rotation to maximize wind force. The peak power coefficients for a cyclogiro wind turbine are greater than that of other turbines.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an apparatus for generating power from wind and which apparatus can operate at relatively low wind speeds and at a relatively high efficiency.

-2-To accomplish the above, the apparatus of the present invention utilizes movable air funnels to maximize the volume and velocity of air in driving the turbine.

An air box design using a dome top and concave bottom is preferably utilized as this allows for an equivalent area for air distribution throughout the three chambers.

In a preferred embodiment, the present invention uses side entrance blow boxes using direction vanes to accommodate a rapid 180 rotation of the air stream with minimum pressure loss. The air from the side entry blow boxes strikes the rotating blades at a sharp angle thereby increasing the blade lift.

In a preferred embodiment, the turbine is equipped with grooved bearing runners at each blade extremity to reduce the flexion and vibration of high rotating speeds.

A preferred feature is the use of deflector blades over the top and bottom of the down wind air exhaust to minimize air pressure exit losses. In one embodiment, there may be used multiple motors for turning the body of the circular air box and positioning the air funnels into the wind.

In one specific embodiment of the present invention, there are provided a second set of cyclogiro blades within the primary air stream. This increases the efficiency of the turbine and reduces the rotational speed of the blades at high wind velocities.

In a still further aspect of the present invention, there may be provided a further set of blades or vanes interiorly of the cyclogiro rotor to generate a higher energy output.

The windmill of the present invention can start producing electrical energy at very low wind velocities and can also accommodate severe cross winds characteristic of' urban areas and roof top installations. Since it is of a relatively light weight construction, it is suitable for installation on either a flat roof or a tower.

-3-BRIEF DESCRIPTION OF THE DRAWINGS

Having thus generally described the invention, reference will be made to the accompanying drawings illustrating embodiments thereof, in which:

Figure 1 is a schematic view of the turbine structure according to one embodiment of the present invention;

Figure 2 is a schematic view similar to Figure 1 of the turbine structure;
Figure 3 is a side elevational view of the frame structure;

Figure 4 is a perspective view thereof;

Figure 5 is a cross-sectional view illustrating the funnel and wind directing structure utilized in an embodiment of the present invention;

Figure 6 is a top plan view thereof;

Figure 7 is a front elevational view thereof;

Figure 8 is a further schematic view of a wind directing structure, with the funnel being removed for clarity;

Figure 9 is a side sectional view showing portions of a wind turbine according to a further embodiment of the present invention;

F'igure 10 is a cross sectional view thereof.

Figure 11 is a perspective view of a modified version of one of the arm and louver arrangements of Figure 9;

Figure 12 is a side elevational view of the modified version of Figure 11; and Figure 13 is a top plan view of a further embodiment of a turbine structure according

-4-to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings in greater detail and by reference characters thereto, there is illustrated in Figures 1 and 2 embodiments of a turbine structure 10.
Turbine structure 10 includes a center shaft 12 having arms extending outwardly therefrom. At the end of arms 14, there are provided vanes or blades 16. This type of turbine is known as a cyclogiro rotor turbine. Included is an upper stabilizing ring 18 and a lower stabilizing ring 20.
Center shaft 12 is mourited in an upper bearing 22 and a lower bearing 24.
Located at the top of the turbine structure 10, there is provided upper drive shaft holding arms 26 while at the lower end there are provided corresponding lower drive shaft holding arms 28.

The frame structure is illustrated in Figures 3 and 4 and which structure includes an upper collar 34 and a lower collar 36. Connecting rods 38 extend between upper collar 34 and lower collar 36 while there is also provided intermediate bracing members 40. Secured to upper collar 34 and lower collar 36 are blow boxes 42 and 44 which will be described in greater detail hereinbelow.

Iteferring now to Figures 5 to 8, there is illustrated a wind directing structure generally designated by reference numeral 48. Wind directing structure 48 includes a plurality of guide vanes 50 along with outlet guide vanes 52 (Figure 8). A
funnel structure 54 is preferably provided; funnel structure 54 is preferably of the retractable variety wherein it is shown in a fully extended position in Figure 5. Thus, depending upon the particular wind velocity, the funnel structure 54 may be moved outwardly or retracted back within a housing.

-5-As will be seen in Figures 5 and 8, guide vanes 50 are arranged to direct the wind at the most preferred angle to the vanes or blades 16 which are rotating about center shaft 12 as indicated by line 46.

As will be noted, the outer guide vanes 50 are arranged to direct the wind through a blow box 42, 44 on either side. Thus, the blow boxes 42, 44 direct the wind at the most favourable angle through the vanes or blades 16.

As may be seen in Figure 3, the structure of the present invention is provided with an upper dome 56 and a lower dome 58. This arrangement allows for an equivalent area or equal velocity for air flow through the chambers which consist of the primary inner chamber and the two blow boxes. The additional area for air flow created by the upper dome 56 and lower dome 58 compensate for the restriction in the cross-sectional area resulting from the addition of the side intakes and blow boxes.

A further embodiment of the present invention is illustrated in Figures 9 and 10 and reference will now be had thereto. The embodiment of Figures 9 and 10 includes many of the components of the previously described embodiment and thus similar reference numerals in the 100's are employed. Thus, the embodiment includes a center shaft 112 mounted in an upper bearing 122 and a]ower bearing 124. Arms 114 extend outwardly from center shaft 112 and mount vanes or blades 116.

Mounted to the same shaft 112 are louvers 162 and which are mounted interiorly of blow boxes 142, 144.

Louvers 162 are mounted, as aforesaid, on the same shaft 112. However, the vanes turn 90 as indicated by reference numeral 164 to create the least drag when travelling upwind and return to the vertical position to recover the most energy when travelling

-6-downwind. This smaller diameter turbine, operating in drag mode rather than in lift mode, increases the overall efficiency of the turbine at low wind speeds and will decrease the breakaway wind velocity. At moderate and high wind speeds, the louvers would generally remain in their horizontal position and do not contribute to generating energy.

The use of the funnel directs the flow of air to the windward face of the rotating blades. The directional vanes bring the area of the face of the blade at an angle which maxitnizes the lift generated. The funnel and blow boxes lead the incoming air over 180 of the upwind face of the turbine. The air funnel may be constructed with motorized reversing drives to extend the funnel in low wind conditions and retract in high wind conditions.

Desirably, the turbine unit is equipped with a positioning drive to orient the funnel into the wind.

Turning now to the embodiment of Figures 11 and 12, there is illustrated a portion of a turbine structure similar to that of Figure 9. In this embodiment, there is provided a center shaft 64 which has a fixed arm 66 extending outwardly on either side thereof.
A louver arrangement similar to that previously described is utilized with the louver being shown in a vertical position as designated by reference numeral 68 to harness the power of the wind while the louver designated by reference numeral 70 is in the horizontal mode when travelling upwind to minimize drag. The louvers 68, 70 are rotatable about arm 66 and there is preferably provided a counterweight 72 at the leading edge of the louvers 68, 70 such that the louvers will automatically return to the correct position when required.

In this embodiment, there is provided an inner lift vane or blade 74 on each end of arm 66. Inner lift blades 74 are similar to outer lift blades 16. Naturally, such outer vanes

-7-or blades are provided, but are not illustrated. Thus, one has three different forces being created from the wind shown by arrow 76.

Figure 13 illustrates an arrangement for further maximizing the power generated from the wind. In this embodiment, one is provided with the first turbine structure 10 followed by secorid and third turbine structures 110 and 210. Thus, the exhaust wind from first turbine structure 10 is directed to second turbine structure 110 followed by the wind being directed from turbine structure 110 to turbine structure 210.

It will be understood that the above described embodiment is for purposes of illustration only and that changes and modifications may be made thereto without departing from the spirit and scope of the invention.

-8-