New 'ray gun' can put out fires
A team of chemists has produced a device that they say can put out fires and could be used by firefighters as an alternative to water or foam.
Firefighters could even point the device at a fire to open up a safe path through the flames for people to excape.
The device is based on a 200-year-old observation that electricity can affect the shape of flames, making them bend, twist, flicker and even go out. It zaps fires with very large electrical fields, meaning they can be put out from some distance and with minimal damage.
The team connected a powerful electrical amplifier to a wand-like probe and used it to shoot beams of electricity at an open flame more than a foot high. Almost instantly, the flame went out - every time.
The device was based on a 600-watt amplifier - about the same power as a high-end car stereo system. However, Harvard's Ludovico Cademartiri believes that a tenth of this wattage could do the trick, allowing the devices to be fully portable.
Cademartiri says that there are a number of different factors causing the flames to go out. Among these, it appears that soot particles in the flame become charged by the electric field, affecting the stability of flames.
"Combustion is first and foremost a chemical reaction – arguably one of the most important – but it's been somewhat neglected by most of the chemical community," he says. "We're trying to get a more complete picture of this very complex interaction."
Cademartiri believes that electrical devices based on the phenomenon could be fixed on the ceilings of buildings or ships, similar to stationary water sprinklers. He says the system shows particular promise for fighting fires in enclosed quarters.
Cademartiri also believes that the technology could potentially improve the efficiency of controlled combustion in automobile engines or power plants.