A new type of extinguisher that uses sound waves to put out fires has been built by two engineering students in the US. Both chemical- and water-free, the invention offers a relatively non-destructive method of fire control, which could find applications in fighting small fires in the home, and the researchers now hold a preliminary patent application for their device.
While the concept of using sound waves to extinguish flames is not new, previous attempts to realize the principle – including efforts by teams at West Georgia University and the US Defense Advanced Research Projects Agency (DARPA) – had not been successful.
Undeterred by this, as well as initial scepticism from their peers and faculty, Seth Robertson and Viet Tran – both final-year undergraduates at George Mason University in Virginia, US – elected to explore the concept, developing a series of prototype sonic extinguishers for a research project.
The principle behind the extinguisher is simple: as they are mechanical pressure waves that cause vibrations in the medium in which they travel, sound waves have the potential to manipulate both burning material and the oxygen that surrounds it. If the sound could be used to separate the two, the fire would be starved of oxygen and, accordingly, would be snuffed out.
SOURCE: Physics World