GE Wind Patents Focus on Blade Design, Protecting Birds

In this last column in our Earth Day 2013 series, IPWatchdog wants to take a look at some of the research and development coming out of one of the industry leaders in wind energy technology, General Electric Company of Schenectady, NY.

GE Wind Energy is a branch of General Electric Company that is involved with the development and manufacture of wind energy turbines. As of 2009, General Electric was the world’s 2nd largest wind turbine supplier, according to Reuters. Wind energy has gained a lot of attention in the alternative energy world because it is renewable and can create electricity without fossil fuel emissions.

These patents and patent applications, published by the U.S. Patent & Trademark Office, outline General Electric’s goals to increase efficiency and reduce manufacturing costs for its wind energy systems. Recently published patent applications include documents filed to protect a more efficiently designed turbine blade and an electronic sensor that can determine if corrosive forces have damaged a turbine blade. Another application is for a light reflective substance that can help warn birds away from turbine blades, which may at first seem insignificant but a major obstacle in the adoption of wind energy are complaints from environmentalists relating to the number of birds killed each year.

GE has also received a few patents recently granting them the legal right to protect certain wind energy system designs. These include a new tapered tip design that increases energy generation efficiency and a new method of pre-assembling internal components to reduce costs.

[Patent-Watch]

Turbine Blade Erosion Sensor
U.S. Patent Application No. 20130089463

Constantly exposed to the elements, wind turbine blades are heavily impacted by forces of erosion, including wind, rain or airborne particulate, like sand. These forces can cause pitting and corrosion on turbine blades, seriously threatening the integrity of the entire wind turbine if left unrepaired. Inspecting turbine blades is time consuming, however, and requires excessive turbine downtime.

General Electric has filed this patent application with the USPTO in the hopes of protecting a method of monitoring both erosion and corrosion on turbine blades. The erosion sensor includes both electrical elements and a material with similar erosion and corrosion properties to the substrate material making up the turbine blades. When the sensor’s substrate material erodes to the point that electrical connections within the sensor are affected, a signal is created that indicates the level of erosion.

Claim 1 of this patent application seeks to protect:

A sensor for monitoring erosion and corrosion of a substrate, comprising: a first element of corrosion resistant material having similar erosion properties to the substrate; and a second element of material having similar erosion and corrosion properties to the substrate; wherein said sensor provides an erosion indicator based at least in part on erosion of said first element and provides a corrosion indicator based at least in part on erosion and corrosion of said second element, said corrosion indicator based on a comparison of the erosion of said first element and the erosion and corrosion of said second element.

Wind Turbine Rotor Blades with Ultraviolet Light-Reflective Substances
U.S. Patent Application No. 20130101417

Bird strikes are often cited as a major drawback to wind energy generation technologies. Birds have difficulty understanding their proximity to turbine blades, due largely to a visual phenomenon known as “motion smearing.” This term refers to the blurring effect that results when an object moves across a subject’s retinas at very high speeds. Motion smear is often worst at the blade tips, the part of the blade that travels the fastest.

This patent application describes a way to make wind turbine blades much more visible to birds by using ultraviolet light-reflective tape. This tape would be applied in separate bands around the turbine blade, from tip to root. As well, the application would protect an ultraviolet light-reflective substance that could be installed underneath a transparent blade coating.

As Claim 1 states, General Electric has developed:

A wind turbine rotor blade, comprising: a body extending between a blade root and a blade tip and including a pressure side and a suction side extending between a leading edge and a trailing edge, the body defining an outer surface; and an ultraviolet light-reflective tape disposed on the outer surface of the body.

Rotor Blade for a Wind Turbine and Methods of Manufacturing the Same
U.S. Patent Application No. 20130101428

Basic design improvements to wind energy generation are aimed at improving the stiffness and strength of turbine blades, which are subject to a lot of wear and high speed movement. Current methods of constructing these blades require much hands-on manual labor, including the layering of sheets of reinforcing material within each blade mold. Reducing the time needed to construct blades would make manufacturing them much less costly.

General Electric wants to protect a new method of manufacturing wind turbine rotor blades that involves machining processes instead of hand labor, which is much more time effective. The blade is constructed from a foam material that includes structural support components embedded within the material. The foam blade blank can be machined into the proper blade shape and covered with an outer skin.

Claim 1 of this patent application describes General Electric’s development of:

A method for manufacturing a rotor blade for a wind turbine, the method comprising: assembling a blade blank comprising a shear member and a volume of core material; removing material from the blade blank to form a body having a pressure side and a suction side extending between a leading edge and a trailing edge, the shear member having a first end disposed adjacent to the pressure side and a second end disposed adjacent to the suction side; and, positioning a skin around an outer perimeter of the body.

Wind Turbine Blades with Twisted and Tapered Tips
U.S. Patent No. 8419371

Wind turbine blades are constructed so that the leading edge of the blade makes consistent contact with the air, which requires some tapering or angle adjustment of the material creating the leading edge. However, one of the factors reducing the amount of energy that a blade can generate involves vortex development occurring at the blade tips. Reducing the aerodynamic load at the blade’s tip, also known as “tip unloading,” can reduce this vortex development, but also the power that can be generated by the blade.

General Electric has earned the right to protect a new blade design that would do a better job of reducing vortex development without having to resort to tip unloading. The backward twist of the blade’s leading edge would range from 6 degrees to 15 degrees. The blade would end in a twisted tip angled in such a way that inhibits vortex development.

As Claim 1 states, General Electric can now protect:

A blade for a wind turbine, comprising: a total backward twist of between approximately 6 and approximately 15 degrees between an outer approximately 1 percent to approximately 10 percent of a rotor radius of the blade; and a total normalized chord change of between approximately one percent and approximately two percent between the outer approximately 1 percent to approximately 10 percent of the rotor radius of the blade.

Wind Turbine Generator and Wind Turbine
U.S. Patent No. 8426995

Manufacturing costs and overall system efficiency are two of the limiting factors on the effectiveness of wind energy generation systems. Some of the manufacturing costs are due to specialized electrical components that must be designed to fit within the small housing within the wind turbine. System efficiency is limited by the inability to test electrical components before constructing the housing, requiring turbine operators to operate components with large margins of electrical load bearing to make sure no single component is overloaded.

This new wind turbine generator design, developed and protected by General Electric, provides for an easily assembled stator, which aids in the transformation of wind energy to kinetic energy within the turbine rotor. Pre-assembled, the stator components can be individually rated to determine the electrical load it can bear. The pre-assembled components also reduce the need for additional electrical connections, increasing the free space within the turbine house and reducing manufacturing costs.

Claim 1 of this official patent protects:

A wind turbine power generator comprising: a stator segmented into two or more stator segments which are configured to operate independently from each other; a rotor rotatably mounted in the stator; and one or more conversion assemblies, wherein the one or more conversion assemblies are mechanically attached to the two or more stator segments.