Patent Application
20140227094
As the inventor noticed that a modern HAWT <Horizontal Axis Wind Turbine with airfoil> stops working on low speed wind, while some sailing boats are still sailing around nearby. That means the boat sail is more efficient to capture the wind.
The efficiency of HAWT, ideally, can be 59.3 percent, in reality, maybe somewhere around 35 percent.
The drawback of a HAWT is that: it is not good at dealing with frequent changes of variable wind conditions; it needs to orientate the direction of the wind; it is very expensive for manufacture, installation and maintenance. Also, it kills birds by accident, about 400,000 a year by some estimates.
VAWT, a vertical axis wind turbine, is more visually appealing, and in theory, should have some advantages over HAWT. But so far both two major VAWT designs have the same drawback: Efficiency. The Savonius rotor's efficiency range 5 to 10 percent, as for Darrieus model with airfoil design VAWT, maybe 30 percent. And sometimes they cannot even start by themselves.
The VAWT and sailing boats share the same upright blade or sail, but why VAWT cannot do better than HAWT?
The drawback of most VAWT's efficiency in large part was because of the additional drag that they have as the back of the blades rotate into the wind.
The key is all these airfoil impeller blades are fixed rigid, by no means to adjust to an optimal angle and avoid the negative impact simultaneously in every single turn. Some other inventions dealt with this issue but did not get a feasible solution.
So there is really something valuable to learn from the boat sail. If we can put boat sails on a VAWT, and find some simple and effective way to control the angle of the sail in response to the wind directly, the result will be greatly different.
Based on the idea, the inventor made a tiny model the size of a toy top, using a piece of thick paper, some paper clips and parts of a pen, and it works! It can start by itself in any direction of the wind. Then I put another one on top of the same post, upside down, in front of a fan, again, both work, but spin in opposite directions from each other!
The present invention related to U.S. patent classification 416: FLUID REACTION SURFACES (I.E., IMPELLERS)
A thorough search of class 416/44, 416/46, 416/119, 416/131, 416/132 was made but found nothing more novel.
A discussion of “Notice of References Cited” Feb. 3, 2014 related to the following prior art which was within those most similar, each contains one or some issues:
The present invention is a solution to all the existing problems with the prior art of the kind, endeavors to provide a simple, low cost yet efficient and reliable vertical axis windmill, featuring:
Something did not show in the drawing and can be different for various applications: Bearings, bearing caps, bolts, transmission and generator or storage.
The present Invention relates to a windmill comprising plural working members pivotally attached to a rotor structure 01 to rotate around a vertical central axis.
The said rotor structure 01 includes upper and lower arms along with a central shaft and bearings.
Each working member incorporates:
The movement of the special hinge bearing 05 is configured to allow the working-part 04 to skew to center-to-bolt radius line of the arm 01 about 30° then swing out 90°, or to allow the same 04 to go beyond the restraint in response to excessive wind then continue to turn around to the next working position.
The device is set to work in such a manner; Suppose the wind blows on a clock pointing the direction of from 6 o'clock to 12 o'clock, with a working member installed on the far end of short hand. At 6 o'clock one side of a working part 04 is facing the wind and pushes the windmill to rotate clockwise until 11 o'clock, then the same 04 swings to other side and continues to push positively until 2 o'clock, at this point the 04 is set free to go against the unfavorable wind like a weather vane until 5 o'clock.
The device could start by itself in any direction of wind, no need of any extra components or sensors for orientation of the wind.
Additionally, the new device is more obvious to birds. Hopefully, this guy will scare away the birds when they approach, and even if some silly birds do fly into it, by nature of the design, pretty much the sails (working part 04) will push away or throw out the victims instead of cutting or killing them. Also, unlike HAWT which is only good at high speed, this machine works even better at low RPM and heavy load like boat sail, and easy to disengage or stop whenever necessary, for example, make a remote or automatic stop on the arriving of flocks of birds.
