The invention relates to generation of electricity from gravitational energy.
An iron pipe, filled with water, is placed vertically and hollow balls made of concrete or wood are driven into the pipe from below. As each ball rises due to buoyancy and is forced out of the pipe, it falls on to a moving platform which is connected to a wheel. The wheel is connected to a generator and electricity is generated, David said.
David sums up his invention as one that can generate "energy anywhere anytime" in every household.
The principle of buoyancy is used to raise the solid objects to the desired height prior to letting them fall on to the platform.
In the copy of the patent granted by the Director of the United States Patent and Trademark Office, it states the requirements of law have been compiled with and it has been determined that a patent on the invention shall be granted under the law.
After close to two decades working in Qatar and Bahrain as a quantity surveyor/ estimator with leading companies, David returned for good to his home in Kayamkulam, about 100 km from the state capital, three months back.
Since then, he has been trying out experiments on his novel project.
"After my wife died a decade back, I did not think of anything else...and only this project was in my mind. In 2008, I applied for Indian patent but am yet to hear from them. I got the US patent last month," David said.
He tried this successfully on a model and is now trying it out on a much bigger scale.
"The new prototype has been prepared using the services of a blacksmith and would be ready shortly," he said.
"From what I have calculated any household can erect this at a cost of just Rs.2 lakh and can meet their electricity demands. The biggest advantage is that this is totally pollution-free and very cheap," David said.
David said his invention is based on continuously converting the potential gravitational energy of falling solid objects on a moving platform to electrical energy.