A new type of acoustic fire extinguisher uses sound to fight flame
Students at George Mason University have developed a new type of acoustic fire extinguisher that uses sound to eliminate flames.
Apparently, we’ve been going at this whole “putting out fire” thing the wrong way. Rather than using water, foam, or smothering it like savages, in the near future we may be using sound to extinguish flames.
A pair of students working out of George Mason University developed a new type of fire extinguisher, according to the Washington Post. The new device uses directed bass that can extinguish flames. It’s still very much a prototype and there needs to be a whole lot more testing, but the possibilities are far reaching and massive.
The students, 23-year old Seth Robertson and 28-year old Viet Tran, came up with the idea as a senior research project. The two spent about a year and $600 of their own money to develop the prototype consisting of a portable(ish) sound generator, amplifier, power source, and a focusing tube.
The pair is working under a provisional patent, which grants them a year to continue their testing on multiple types of fires. So far the prototype has only been used to put out fires created with rubbing alcohol, but that testing will expand to fires caused by other flammable chemicals, and fires burning different materials ranging from wood to paper to metals and beyond.
The hi-tech fire extinguisher was initially conceived as a device to eliminate kitchen fires and avoid the toxic contaminate monoammonium phosphate found in commercial fire extinguishers. The possibilities go far beyond though, and the pair hopes that one day it could be developed to work on a larger scale to put out things like forest fires. Really, anywhere that using water or chemicals is inefficient.
Robertson and Tran are electrical and computer engineers, which instantly put them in an odd position, and doubters criticized them for their lack of chemical engineering. As part of their senior project, they needed a faculty adviser to oversee them, but several refused. Eventually, professor Brian Mark agreed to act as adviser, but he did so skeptically.
“My initial impression was that it wouldn’t work,” Mark said. “Some students take the safe path, but Viet and Seth took the higher-risk option.”
The students came up with the idea after seeing research that showed sound waves were capable of manipulating flames. At a certain frequency, sound waves can separate oxygen in the fire from the fuel.
“The pressure wave is going back and forth, and that agitates where the air is,” Tran said. “That specific space is enough to keep the fire from reigniting.”
It took a fair amount of trial and error, but they eventually discovered that bass in the 30 to 60-hertz range could consistently extinguish flame.
In 2012, DARPA experimented with a similar system of “acoustic sound suppression of flame.” It determined that it could work on small levels, but not “the levels required for defense applications.” That “defense applications” phrase could leave a lot of room for other applications though.
The major issue now is that while the bass can eliminate the flames, it doesn’t address the heat. Even if the flames are removed, if the fuel source remains hot enough, it could simply rekindle itself. Still, the students have shown that dropping the bass on a fire can potentially kill it.
There’s a song in there somewhere.
Robertson and Tran will continue their work on the device, but unsurprisingly, both have big jobs waiting for them when they graduate this May.