VERTICAL AXIS TURBINE HYBRID BLADES

Description

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a vertical axis wind turbine, and how to make its blades perform better. Drag and lift blades each have their own benefits and drawbacks; the possibility of combining them for better total performance is presented. Drag blades operate from the push of the wind; lift blades operate like the wing of an aircraft by inducing circulation changes.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 is a diagram of hybrid and tapered blades.

FIG. 2 is a diagram of a hybrid drag and lift design.

FIG. 3 is a diagram of arms to hold the blades.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention shows vertical axis turbine blades that deliver solutions to the problem of providing maximal power and maximal quiet at the same time. Vertical axis blades are less powerful when working in a drag configuration (being pushed by the wind) and noisier but more powerful when working in a lift configuration (with an airfoil-type effect). Lift configurations also have more trouble starting. Therefore, this application attempts to bridge the gap between the two types of configuration by presenting several solutions that increase power to a basically drag configuration or decrease the noise of a lift configuration.

Definitions: The environment of the inventions can be any fluid. The term “wind” is often used because it is most common, but the inventions mentioned are adaptable to any fluid, whether gas or liquid. Foils are as generally known in the aircraft industry. If a non-blade foil shape is close enough to a blade to affect its performance, it is functionally adjacent to it. Any reference to such a structure is distinct from foil shapes that may be on the blade.

The principles and operation of a vertical axis turbine according to the present invention may be better understood with reference to the drawings and the accompanying description.

Referring now to the drawings, FIG. 1 illustrates a group of hybrid lift and drag blades. We introduce the device of vertical axis turbine blades, or alternatively any blades, being made, at least partially, of an outline foil shape. In FIG. 1, the bottom of the picture shows an open blade with a shape on the edge, ideally the outer edge, that curves back in the direction of the inner edge. One way to define it is any outline blade that passes beyond the imaginary line of a half structure. In another embodiment, any blade with a portion that passes that imaginary line and also turns toward the inner edge is included (FIG. 2).

FIG. 1 also illustrates the use of different blade shapes in vertical axis turbines, in one embodiment, of the Savonius variety. In one embodiment, the blade itself tapers in shape, either larger or smaller at the periphery or at the center. The reason is that with a superior and inferior foil, or even just an inferior one, a shape that is not vertically linear may take more advantage of higher velocities near the foils. The blade itself may change shape along the vertical distribution by being a regular drag blade in one location and a lift blade in another location as shown. A transitional area may occur. The objective is to take advantage of different velocity patterns in connection with the foils. In another embodiment, each of the above is claimed in association with a foil.

In summary, (1) and (2) are different types of lift type blades, (1) being a complete foil. (3) illustrates how the geometry of (2) involves crossing the chord midline part way. (4) is an example of a drag type of blade. (5) shows how they can be combined vertically. In this case, the lower and upper parts are drag, and the middle part of the blade is lift. The opposite is also possible. (6) illustrates a tapering shape. The reason for this is that a turbine with a lower or upper foil produces a distribution of higher velocity air even a little in front of the foil shape (8), so that a tapered shape that bulges at the middle can contact that area of higher velocity. This bulge shape of blade is claimed for drag and lift varieties, and for association with a foil. For orientation, (7) is the shaft.

FIG. 2 is an example of a blade design with one side curved over on itself that can combine elements of lift and drag in one blade. It is claimed by itself and in association with an FDD foil. The part (9) functions exactly as drag. The special point about the angle between the points 10 and 11 is that the inward turning angle directs wind into the center of the blade in drag configuration while functioning to deliver some lift due to the foil like appearance.

FIG. 3: The arms holding the blades in a VAWT can be in a streamlined collector shape facing the direction of movement of the turbine, either sharp (12) or rounded like a cup (13), so that they can help start the turbine. This combines some drag with lift or adds to the drag.

While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.

SUMMARY OF THE INVENTION

The present invention successfully addresses the shortcomings of the presently known configurations by providing devices for obtaining simultaneous drag and lift effects with a vertical axis turbine.

It is now disclosed for the first time a blade (defined as including a blade segment) of a vertical axis turbine, comprising:

a. at least two regions of different shapes in a vertical distribution along the blade. (Note that this does not refer to a different shape at the very edge, such as a winglet, which is known art. All these descriptions refer to more than minimal changes or purely esthetic curves added to the blade design. The regions of two different shapes as described here include the possibility that there may be an area of gradual transition from one shape to another.)