CA2403607C

CA2403607C - Self-directing wind turbine

Info

Publication number: CA2403607C
Application number: CA002403607A
Authority: CA
Inventors: Omeed Neekon
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-10-03
Filing date: 2002-10-03
Publication date: 2006-08-01
Anticipated expiration: 2022-10-03
Also published as: CA2403607A1

Abstract

An improved, self directing, horizontal axis wind turbine for conversion of wind energy into useful work including generation of electricity. The said wind turbine is comprised of a plurality of two or more blades mounted on a rotor assembly rotating in a conical path about the horizontal rotor shaft downwind from the support tower. The rotation of the blades caused by the wind is transmitted to an electric generator to produce electricity. The embodiment of the said wind turbine and the electric generator along with the attachments including the generator housing are mounted on the horizontal section of a vertical shaft which is supported with bearing assemblies on the support tower. The said turbine and the vertical section of the shaft freely rotating around the support tower in response to the direction of the wind.

Description

SPECIFICATION:
This invention relates to horizontal axis wind turbines and in particular a wind turbine that is self directing in response to the wind direction without requiring a rudder mechanism. This wind turbine has features to simplify the design and construction of the blades and blades assembly, while providing improved protection against destructive forces of winds of high velocity.
Wind mills and wind turbines of various types have been in use for thousands of years.
Persians were the first to use the windmills for grinding wheat and for irrigation.
One major problem with the existing wind turbines especially with the horizontal axis type is the detrimental effect of high winds on these turbines- This is especially true with the wind turbines that utilize a rudder to direct the rotating blades into the wind i.e. in an up-wind direction in relation to the position of the supporting tower. The enormous force of high winds pushes the rotating blades assembly into the support tower and destroys the wind turbine. Even in down-wind type turbines with a rudder mechanism to direct the rotating blades assembly into the wind but downward and away from the supporting tower, the conflicting forces induced upon the wind turbine as a whole, becomes detrimental. In high winds especially in shifting winds with high velocity, the force of the centrifugal torque of the rotating blades assembly in one hand, and the sudden force of the shifting wind on the rudder act in conflict and in opposing geometry, eventually breaking apart the turbine.
A second problem with most wind turbines is the complexity and the high cost associated with the blade design and installation process. Most modern blade designs require complex design and manufacturing processes to layout and shape the desired airfoils.
The complexity of such processes contributes to higher costs for building turbine blades and their installation on the rotor assembly-The present invention disclosed herein represents significant improvements to overcome both of these maj or problems using simple yet highly effective design principles as descn'bed in greatea~ details in the following disclosure of the invention and the referenced drawings.
Brief deacriution of the dra Figure 1 is a side view of the present invention and shows the main components of the self directing and improved wind turbine. It shows the tower 1, the bearing assemblies 2, the main shaft 3 with a vertical section exteflding inside or along the support tower, and a horizontal section supporting the rotor assembly and the generator assembly.
The figure also shows the generator housing 4, generator 5, motion transmission assembly 6, turbine arms assembly 7, byes asseanbly 8, rotor assembly 9 and the mounting plate 10 for mounting the arms assembly. Figure 2 is a front view of the blades 8, arms 7, rotor assembly 9 and the mounting assembly 10 shown as a circular plate.
Figure 3 shows the design for building a one-piece double-arm assembly. A
blade is later mounted on each end of this arm. The angle 7-1 shows the angle for bending the arm plate. Figure 4 shows the one-piece double~arm assembly after being bent on both ends, in the same inward direction. The angle 7-2 shows the degree of the bend.
Figure 5 is the layout of the blade design. It shows the layout of two blades each having a section 8-1 designated to act as the mast or the leading edge of a sail, section 8-2 designated to act as the body of the sail, and section 8-3 to act as the trailing end of a sail.
These three areas of each blade cause each blade to act as a mainsail. The rectangular material (preferably aluminum sheets of no less than 1/8 inch in thickness) is cut in half along the solid line, and bent along the dotted lines. The black triangles are trimmed out to complete the two blades as indicated by the arrow 8-4 pointing to the finished blades in Figure 6.
Figure 7A and 7B show the design improvanent to reduce tlx destructive "push force"
and change it more into "lift force", it also indicates how the outer tip of the blades at the lower edge of the "conical path" is farther away from the support tower which again helps prevent contact of the blades with the tower. Figure 8 is an enlarged picture of the sail-shaped blade design, Figure 9 demonstrates the "conical path" of the blades in motion.
Disclosure and full deacri~lion of the best wav to build and use the invention~
In drawings which illustrate the embodiment of the present invention, Figure 1 is a side view of the wind turbine and related attachments mounted on top of a supporting tower 1.
Tower I ideally has a six-sided tubular metal construct that is wider at the base and tapers towards the top of the tower. 'The tower is installed in a vertical position using long and heavy bolts and nuts to firmly attach the base plate of the tower to a strong foundation in the ground. Additionally the tower is secured in its vertical position by means of high strength cables and wires. The attachment point of these cables on the tower is positioned a safe distance below the top of the tower in such a way not to interfere with the rotation of the turbine and the blades in all directions.

The main shaft 3 has a vertical section exiling downward and inside the tubular tower 1, and secured in a vertical position by means of at least two bearing assemblies 2. One of the bearing assemblies is mounbod at the top of the tower, and the other one a good distance down and inside the tower, holding the vertical section of the main shaft, and allowing it to swivel and horilly in either direction.
The horizontal section of the main shaft has an angle of about 95 degrees (no less than 93 degrees and no more than 100 degrees) relative to the vertical section of the main shaft.
There are two advantages to this design feature. First, this angle of about 95 degrees causes the lower part of the rotating blades to be additionally further away from the tower to prevent any potential contact of the blades with the tower in shifting high winds.
Secondly, this angle of about 95 degrees helps produce a gravitational force on the turbine assembly to slightly offset the downwind force of the high winds that would tend to push the turbine assembly in a downwind direction. The horizontal section of the main shaft is used to hold and support ail other components of the turbine assembly including components 4 through 10 as shown in Figure 1.
The generator housing 4 is comprised of a frame and a cover assembled firmly (welded) onto the horizontal section of the shaft 3. The cover of the housing 4 is made in such a way to allow for ease of mounting and maintenance of an electric generator on the said frame, and protect the generator against natwal elements i.e. weather, rain etc.
The said generator is further connected to a motion transmission mechanism 6.
The rotor assembly 9 is firmly ate securely attached to the end of the horizontal section of the main shaft 3. A large pulley together with the mounting plate 10 and the rotor assembly 9 are firmly sandwiched togetl~ by means of strong bolts and nuts.
This method provides for the maintenance flexibility to replace or repair these parts individually. The said large pulley is then connected to a smaller pulley on the shaft of the electric generator through a belt. Other motion transmission alternatives such as gearboxes or chain and sprockets can also be used instead of pulleys and belts.
'The mow~ting plate 10 is required for t~abines with odd number of blades e.g.
a three-blade turbine assembly. In a two-blade or four-blade design, the arm assembly 7 is chosen with a larger width to be easily sandwiched at the center bo the rotor ass~ably, eliminating the need for additional mounting plate 10. The present invention ideally comprises a wind turbine with three blades.
As illustrated in Figures 3 and 4, the arm assembly is bent at equal distance from the center of the arm assembly. In a three-blade turbine, the arm assembly in Figure 3 is cut at the center to prod~e two disjoint arms. A third arm is built in a similar way. The three arms are then mounted on a mounting plate 10 shown in Figures 1 and 2.
In a two-blade or four-blade turbine, the arm assembly shown in Figure 3 remains one piece, bent on both ends as shown. The arms assembly is bent at about 45 degrees indicated by angles 7-1. The amount of bend 7-3 in Figure 4 is about 20 degrees.
This twist in the arms assembly provides for the required inclination for the end of the acme 7, outward and away ffro~ the rotor ably 9 as shows in Figure 1.
Consequently the blades are positioned to rotate in a conical path downwind and away from the tower 1 as shown in Figure 1. The amount of the bend indicated by the angle 7-2 in Figure 4 also defines the pitch of the blades i.e.
approximately 20 degrees in relation to the direction of the wind. This is a simple yet highly effective feature of the disclosed invention.
As demonstrated in Figures 5 and 6, section 8-l of each blade is bent along the dotted line for about 30 degrees. Section 8-3 is bent approximately 20 degrees along the dotted line. Each blade therefor has a scoop shape similar to the mainsail of a sailboat.
The blades 8 and anus 7 are then mounted and coupled with the rotor assembly 9 and the mounting plate 10 (optional for turbines with even number of blades as described earlier) as shown in Figure 2. Once assembled, the inside scoop of the blades will face the tower 1 as shown in Figure l to catch the wind and start rotating. Properly assembled blades will rotate in a direction such that section 8-1 of Figure 5 is the leading edge of the blade while section 8-3 of Figure S acts as the trailing edge of the blade.
The center of gravity of the turbine assembly comprising of components 4 through 10 as shown in Figure 1 is outside and away from the axis of the vertical section of the main shaft 3. This makes it possible for the complete turbine assembly including the vertical section of the main shaft 3 to swivel about the vertical section of the main shaft 3 in either direction in response to the wind direction, hence a self-directing wind turbine.
9~

Claims

1. A self-directing horizontal axis wind turbine comprising a wind turbine assembly, an electric generator, a frame and housing for the said generator are mounted on a short horizontal section of an inverted L-shaped main shaft; the said main shaft comprising a long vertical section and said short horizontal section, having one end fixedly connected to the top of the vertical section with an angle no less than 93 degrees and no more than 100 degrees, the said vertical section of the said main shaft is mounted inside or alongside a vertical support tower, the said vertical section is held securely by means of at least two bearing assemblies allowing the said vertical section of the said main shaft to rotate freely in either direction as a result of the wind force upon the said wind turbine assembly itself without the use of any rudder mechanism hence self-directing.

2. The self-directing wind turbine of Claim 1 wherein the said wind turbine assembly further comprising a rotor assembly, a mounting plate, two or more blade arms each for mounting a sail-shaped blade on the said blade arm, a motion transmission mechanism to rotate the said generator in connection with the rotation of the said rotor assembly; the said rotor assembly is mounted upon the said horizontal section of the said main shaft, the said rotor assembly and the said mounting plate and the said arms and the said motion transmission mechanism coupled together and as a whole rotating about the axis of the said horizontal section of the said main shaft.

3. The self-directing wind turbine of Claim 2 wherein a minimum of two blade arms mounted on the said mounting plate and having the outward end section of each said blade arm bent at approximately 45 degrees of slant for approximately 20 degrees in relation to the plane of the central section of the said blade arm, such central section of the said blade arms being coupled to the said rotor assembly either directly or by means of the said mounting plate, the said rotor assembly further coupled with the said motion transmission mechanism.

4. The self-directing wind turbine of Claim 2 or 3 wherein sail-shaped blades comprising a leading section, a middle section and a trailing section are mounted on the said blade arms in such a way that one such blade is mounted on each said blade arm, and the scoop of the blades are facing toward the tower making each blade act as a mainsail of a sailboat to capture the wind blowing in a downwind direction relative to the said tower.

5. The self-directing wind turbine of Claim 4 wherein the said wind turbine assembly is downwind in relation to the said support tower and rotates in a Self-directing Wind Turbine CLAIMS Continued:

predetermined circular direction while the travel path of the blades defines a cone-shape or conical path about the axis of the said horizontal section of the said main shaft, while the said self-directing wind turbine freely moves about the said vertical section of the said main shaft in response to the wind direction.