Using beams of electricity to extinguish fires?

I just read about this: Taming the flame: Electrical wave “blaster” could provide new way to extinguish fires

Apparently, they can shoot electricity at fires to put them out. How the hell does this work?

The article briefly mentioned:

But is that it?


I’m intrigued and confused.

Well…this is just a WAG, but electric arcs can turn molecular oxygen (O[sub]2[/sub]) into ozone, right? Fire needs O[sub]2[/sub].

From the linked article:

So firemen, already one of the coolest jobs, now get proton packs (ok ok: electron packs).

Meanwhile the sexing up of software development is long overdue…

…although OTOH, firefighters will now have to dress like this, so it’s not all good.

Just don’t let the beams cross!!

Fire needs a oxidizer which I believe O3 is more reactive then O2. Also I think you can use Cl or F as well.

Well, my guess is that the best way to explain the effect (I’m assuming the effect is real) is by noting that a ‘fire’ can be thought of as two things: a chemical reaction where a fuel is being oxidized, and flames, which are hot gases and soot rising off of the fuel. The flames carry heat away from the fuel, and often onto other fuel, extending the fire. The flames also allow fresh air to flow in underneath, providing more oxygen for the reaction.

If the soot particles are indeed charged and can be pulled by an electric field, they’d tend to draw the gases with them. So you could control where the flame goes so instead of rising straight up as a normal flame does, it would point sideways to some degree.

Now, I don’t know how much you really could do – I suspect the researcher is saying “maybe you could do these cool things or maybe the effect is too small to do anything useful, but we don’t know yet. Let’s find out.” But if the effect ends up being big, then you could pull flames sideways (again, by pulling the soot particles in the flame) or even try and get them to sit back down on the fuel. If you got the flame to sit back down on the fuel, not much oxygen could get in and the fire would go out (just like a match in zero-g and normal atmosphere will go out by itself). Getting a flame to move downwards seems pretty tough though, so I don’t have huge hope for an electrical fire extinguisher.

We know it’s possible to extinguish fires by quickly moving the hot gasses away from the fuel source. That’s what happens when you blow out a match, or when they snuff an oil well fire with explosives. “Blowing out” a fire is a balancing act though – the wind that carries the hot gas away also brings in fresh oxygen.

This new approach suggests that there may be a way to move the hot gasses away from the fuel without using high winds or explosives.

I have no idea how this works, but a flame is a type of plasma, and if highly conductive like other plasmas, current or voltage may be able to disrupt the plasma condition, perhaps extinquishing the flame. Electrically induced plasmas have to be maintained with a carefully balanced proportion of ions. I’m not sure how that works in a flame, but changing the balance of charge should have some effect.

“they connected a powerful electrical amplifier to a wand-like probe and used the device to shoot beams of electricity at an open flame more than a foot high. Almost instantly, the flame was snuffed out”

Uh, what?

Either the reporter removed all technical terms and replaced them with something else, or they’re describing a public demonstration.

“Amplifier,” sure it’s not a high voltage supply?

So, what happens when you put a small candle on top of a VandeGraaff machine?

Flames normally aren’t very conductive, but it depends on the burning material. For example, to build a “flame speaker” using stove gas, you need to inject lots of ions using a fiberglass wick wet with salt solution.

I spotted this brief pieceon the subject. I’m wondering if the introduction of current or voltage is turning the flame into some kind of conductive plasma. IIRC flames need a particular shape in order to be sustained so that enough oxygen comes in contact with the hot fuel. Maybe that’s how it works.

wbeaty, you were the guy I thought would have an explanation. Have you seen the scotch tape X-ray thread? I recall a story on your site about a weird event at a plastic manufacturing site where plastic sheet was being wound or unwound from rolls. Maybe some connection there.